In the backstory of Naruto, the Fourth Mizukage, Yagura, led the Hidden Mist Village during the years of the Bloody Mist, where half of each graduating class was required to murder the other half in cold blood, one of the village's most famous ninja lead a failed coup, an entire Cipher Division being cut down by their own bodyguard was considered proper procedure, and Kisame (the aforementioned bodyguard) even told Yagura to his face that the latter would have him eliminated at some point. Apparently, people thought highly of Yagura, which could be true, because either Madara Uchiha or Tobi/Obito was mind controlling him the entire time. The fact that Yagura was being controlled by the Akatsuki leader has become public knowledge in the Mist Village, as numerous characters have blamed Akatsuki for the Bloody Mist years.
King Hamdo of Now and Then, Here and There is a petty, raging tyrant who expends his armies of enslaved Child Soldiers at will. His first scenes involve strangling his cat when it upsets him, and then having the child protagonist tortured for hours and hours on end.
The World Government of One Piece appears to fall into this, although not the Marines protecting it. The World Government itself is incredibly corrupt and brutal, being major patrons of the mostly pirate-run slave trade and using the Marines for acts of mass butchery to silence those that found out their dirty secrets or could threaten them. The nobility of this world is even worse, as the upper-middle class will cheerfully burn an occupied city to the ground to make things look neater for a World Noble's visit and claim it's the poor people's fault for being too stupid to be born nobles. The highest social class are so batshit insane they wear air bubbles to prevent themselves from breathing the same air as commoners and regularly murder anyone they encounter them over the very pettiest gripes.
Villains who actually work for them is a case-by-case basis. For example, most of the antagonists in the Inpel Down arc are just as Axe Crazy and sadistic as any noble, with the notable exception of Magellan, the Big Bad of the arc; he was the closest anyone in the prison came to an Anti-Villain and a Reasonable Authority Figure, despite being loyal to his employers.
Were he to achieve his goal of taking over Fishman Island, Hodi Jones would easily be this - his immediate plans would be to slaughter anyone on the island who wants to live in peace with humans, followed by going to a council of kings with the intended purpose of murdering them all.
Queen Himiko from the Dawn arc of Phoenix, who then dooms her kingdom by exiling her Brother when he finally tells her enough is enough.
Kano from Texhnolyze, the Big Bad. While very intelligent, charismatic and eloquent, he's a deranged solipsist who believes that he's the only real person in a world that exists inside his mind. A possible explanation for this may be the fact that he's the result of generations of selective inbreeding, designed to create the perfect ruler.
Light Yagami, a.k.a. Kira, of Death Note certainly qualifies in the later part of the show, as his reign is based strictly on his personal idea of justice, not to mention that his god complex consistently gets in the way of his judgment. Those who disagree or stand in the way have about forty seconds to live.
The Valerian sovereign in Tsubasa Reservoir Chronicle. According to a letter of distress, he starts indiscriminately murdering people and having their corpses dumped in the Sinners' Valley in his "fits of insanity." Then, after he believes that everyone else in Valeria is dead, he jumps in himself and commits suicide in front of Yuui. The Valerian people chalk his insanity up to the curse of the twins.
Former Shi'ar king D'Ken, who is at least partially responsible for Vulcan being as screwed up as he is, was another fine example (until he was killed by, you guessed it, Vulcan).
The 1994 story "The Great Pretender" (the first in a miniseries of Showcase issues each featuring a different Batman villain) shows us an alternate Gotham City in which the Joker has apparently taken over everything and crowned himself "King." In addition to his usual cold-blooded murders, King Joker makes his subjects take baths in custard, has all government employees dress in Elizabethan-era costumes, and broadcasts his decrees via giant video screens towering over the streets of Gotham. And as if all that weren't wild enough, there are numerous crazed men running around in white makeup and green hair dye who seek to overthrow King Joker, including an amnesiac who believes he is the Joker. Plus, various Batman impostors are also roaming the streets to do battle with all these faux Jokers. Yeah, it gets pretty crazy.
He also exhibits some of these characteristics in the 1989 movie, such as when he appears at the Gotham City 200th Anniversary Parade seated on a throne (in Real Life an actual throne, donated by the King of Sweden). He also, like Nero (see below), fancies himself a Mad Artist, although his "masterpieces" are mostly just vandalized or outright destroyed works by other artists or human victims whose faces he has perversely scarred. He even has one of his Mooks carry around a boombox playing a song whose first verse announces: "All hail the new king in town!"
Conan the Barbarian came up against mad and corrupt kings with some regularity, but the most notable of these was King Numedides, who Conan overthrew to become king of Aquilonia. Numedides regularly had men and women flayed alive for minor transgressions; indeed, when Conan was imprisoned in his tower, Numedides executed a dancer who Conan liked and ordered a scrap of her flesh tossed in Conan's cell. Conan immediately recognized whom it belonged to because of the dancer's many tattoos. As well, in order to become immortal, Numedides enlisted the services of the Evil Sorcerer Thulandra Thuu; together, they sacrificed young women in order for Numedides to bathe in their blood.
The Red King, main villain of the Planet Hulk storyline, fits this trope to a T.
Like Conan, Red Sonja has come up against her fair share of mad kings. Unlike Conan, most of them attempted to imprison her in their harems. Bad move.
Sin City's Roark Junior, a.k.a. That Yellow Bastard, would have been this if he was able to inherit his family's political power. He was an insane and violent sexual deviant who preyed on kids... and was being groomed as a future US president before he met his end.
In the Dark Empire arc of the Star Wars comic lines, Palpatine became this after his first resurrection. Although he was definitely not a good person prior to his first death in Return of the Jedi, he at least was sane enough to actually succeed in his plans and manipulate factors in his favor. Afterwards, he's become just yet another insane, megalomaniacal tyrant. (His increased insanity was heavily implied to be the direct result of transferring his spirit into clones.)
It also probably didn't help that said clones were being sabotaged by one of his guards to genetically break down.
Vulcan (from the Summers' Tangled Family Tree) becomes king of the Shi'ar empire and essentially drives the people to hell, dividing them and thus starting the War of Kings.
Chief Judge Cal in the Judge Dredd story "The Day The Law Died" (collected as Judge Caligula) is, as the name suggests, closely based on the Emperor (even being drawn to resemble John Hurt in I, Claudius). Caligula (allegedly) made his horse a senator; Cal made his goldfish Deputy Chief Judge. Caligula demanded grandiose building projects; Cal expected the citizens to build a mile high wall around Mega-City One in a week. He also argued with deceased former Chief Judges, preserved his execution victims in vinegar, and sentenced the entire city to death twice. At least the mile-high wall actually helped protect the city later on.
In "The Hour of the Dragon," Valerius fits this trope perfectly: his drunken revelry, sexual violence and senseless slaughter was so extensive that his co-conspirators had to step in, to stop him from running the kingdom into the ground.
In A Brief History of Equestria, it is shown that while most of the founders of Equestria were Flanderized in the Hearth's Warming Eve pageant, Chancellor Puddinghead, on the other hand, was toned down, elected via youth vote and managed to get killed shortly after Hearth's Warming in a stupid dare. Among many, many, other things like appointing her pet parrot to her cabinet, which it retained even after it died.
On the other hand Commander Sullamander, Hurricane's predecessor, was less the humorous type and more the savage dictator type, who in her last years formed a Cult Of Personality around herself. General Wind Whistler was able to lead roughly two-thirds of the pegasus military against her when the coup came, since she was that hated.
Eugenesis has Galvatron, who spends most of his time either just sitting on his throne not doing anything, or having hundreds of troops killed for non-existent plots to poison his drinks. It's mentioned that before he came back from wherever it was he'd been, the Decepticons under Soundwave had almost taken back all of Cybertron. The only reason they don't get rid of Galvatron now is because he's Galvatron.
Film - Animated
Kuzco from The Emperor's New Groove is one example where The Caligula in question is the Main Character, although he's spoiled, feckless and self-absorbed rather than outright insane. He gets better.
The film implies that his being in the trope at the start of the movie was due to Yzma's influence when he was growing up. Yzma plays the trope straight. After throwing him off the throne, she became all the things of a stereotypical Caligula, especially outright madness.
Roberto is depicted as one in Futurama: Bender's Game, having sent his entire army out to wage war on scallops, but sunk the ships wiping them out.
King Koo-Koo, the ruler of Loony Land in Raggedy Ann & Andy: A Musical Adventure, is a textbook example of this - even by the standards of his realm. The only thing in existence he seems to care about is his frustration at being extremely short, which he is determined to fix by granting himself endless opportunities to laugh at other people (since laughing makes him swell up to the size of a Macy's Thanksgiving Day Parade balloon). To this end, he has his Dragon, the crazed knight Sir Leonard Loony, play all kinds of practical jokes on anyone who visits his court (and even keeps an entire wagon full of cream pies on hand for Pie in the Face gags), all the while making his courtiers laugh so hysterically that over time they have degenerated into zany robotic monstrosities. He ultimately crosses the Moral Event Horizon when, in his bid to become the largest being who ever lived, he has a giant squid-monster who is his friend entertain him by trying to literally tickle all the good guys to death.
King Candy from Wreck-It Ralph, who rules the world of Sugar Rush. He can be seen as somewhat kooky as he actually participates in (and always wins) the daily races. But, in reality is actually Turbo, an arrogant racer from the 80's arcade game Turbo Time. As Turbo, he went into the game's mainframe, removed Vanellope's data and everyone's memories of her, and adopted the persona King Candy.
Film - Live Action
In 13 Assassins, Lord Naritsugu is the Shogun's little brother, and uses his position to commit all manner of horrific atrocities, such that his house's vassals start committing seppuku in protest. The main conflict of the movie is that the Shogun wants him killed without dishonouring their house.
The Alternate Universe version of Biff Tannen in Back to the Future: Part II. Using the Gray's Sports Almanac he obtained from his future self, he wins an insane amount of money from gambling, which he uses to become mayor and buy off the police, turning Hill Valley into a Mad Max-styled city.
In the Woody Allen film Bananas, the rebel leader Esposito goes mad with power the second he gains control of San Marcos. For your consideration, his speech to the people of San Marcos:
"From this day on, the official language of San Marcos will be Swedish. In addition to that, all citizens will be required to change their underwear every half-hour. Underwear will be worn on the outside so we can check. Furthermore, all children under 16 years old are now... 16 years old!"
The Roman Emperor Commodus as depicted in Gladiator and The Fall Of The Roman Empire. Commodus wasn't as bad in real life as he was in either film, but he still wasn't the sort of monarch you'd take home to mother — he once walked into the Senate with a severed ostrich head, fought as a gladiator in the arena (against disabled opponents who stood no chance)note which was actually a lie part of the "Damnatio Memoriae" operation the senate organized against him after his death. In reality, he was actually widely recognized as the best arena fighter of the time, and is best-known for ending the "Five Good Emperors".
Swan, the villainous record producer of Phantom of the Paradise. Though he styles himself as an Affably Evilmanipulator, almost every single decision he makes in the film is made on a whim: his employees are hired, fired or reassigned on the flimsiest of reasons, he imprisons his stars in torturously ironclad contracts, rewrites the Phantom's music to cater to his own eccentric tastes, and orders his fiancée assassinated at his wedding for the sake of publicity. Worse still, not only is he in complete control of the music industry, he's also immortal.
Then there's Quo Vadis?, which gave us a delightfully mad Nero played by Peter Ustinov. Arguably one of the best things in the whole movie.
Admiral General Aladeen from The Dictator. Among other things, the guy has his own men executed for the most trivial reasons such as his nuclear missile program head not having made the missile pointy or one of his men accidentally blocking him on a staircase (though it turns out his executioners are rebels and everyone he has ordered killed is alive and living in New York), he hosted his own "Aladeen Games" where he won every single event (one event shown being a race where he shoots the other athletes in the leg and has the finishing line carried forward to break it) and changed a large percentage of the words in the language in his country to "Aladeen"...including contradictory words like "positive/negative" and "open/closed", causing immense confusion. All Played for Laughs, naturally.
Aedenoid Hynkel from The Great Dictator, a parody of Hitler who even dances with a globe of the world as he thinks of becoming 'Emperor of the World'.
The King of The King and the Clown is based on the Korean ruler Yeonsangun of Joseon. In the film he is ruthless and erratic in his behavior, but also very cultured and rather sympathetic at times, with loads of Freudian Excuse.
The portrayal of Idi Amin in The Last King of Scotland exemplifies this trope almost perfectly. He begins as an Anti-Hero and descends into complete madness and insanity.
Harold Shand, anti-hero of the classic 1980 British gangster movie The Long Good Friday. He begins as a competent mob boss with grand ambitions, who nonetheless seems sane and grounded. After a series of mysterious and violent incidents chip away at his criminal empire, he gradually falls apart; by the end of the film he has slit the throat of his most trusted lieutenant, alienated his most valuable business partners, and had his fellow gang bosses strung up on meat hooks. It all ends badly.
The roman dictator Sulla is portrayed as this in the 2002 film version of Julius Caesar. His political ambitions to maintain the senatorial system is glossed over and he invades Rome and orders purges just to seize personal power. He massacres all his enemies, orders Caesar's heart cut out by Pompey, and sentences a coin minter to death because he felt like it. His tyranny ends when he drowns in his own bath due to a heart attack.
K. A. Applegate loves this trope, and all of her series feature it to varying degrees:
Visser Three from Animorphs fits this trope like a glove. In the main series he's an Ax-CrazyEvil Overlord who executes subordinates at the drop of a hat, meets every threat that comes his way with overwhelming force, and due to being the only Andalite-Controller and having a bastion of Eldritch Abomination morphs is a Physical God by the definitions of this series. The prequel Chronicles books show his backstory as a quite sane and capable Manipulative Bastard who climbed from obscurity by studying the Andalites when no one else would. This study led to his obsession with becoming the first Yeerk to infest an Andalite, a goal he eventually reaches. Once he hits that high mark, there's nowhere else to go but down.
Most of the gods portrayed in the series Everworld fit this description perfectly. Almost every god that the main characters encounter, regardless of what mythology they originate from, has an utterly apathetic regard for life in general (being gods and all) and shows a certain degree of sadism, though some of them (especially Neptune) are simply bat-shit insane.
In RemnantsTamara's baby. It was damaged by whatever they were exposed to on the journey over, and grew up quickly into a monster, who led humans and then some of the aliens.
A.E. van Vogt's Empire of the Atom and The Wizard of Linn has most prominent characters as analogues of Roman history, starting with Clane/Claudius. "Calaj" is the obvious Caligula stand in, the grandson of Lydia/Livia and related to Clane and Tews/Tiberius.
King Ademar of Gorhaut in Guy Gavriel Kay's A Song For Arbonne has rabid dogs tearing each other to pieces before the throne and maids give him blowjobs right in front of a very discomfitted court, among many other strange hobbies.
A Song of Ice and Fire gives us both King Aerys II "The Mad" Targaryen and King Joffrey Baratheon (who knew a 13-year-old could be that psychotic?). The former was the worst King that Westeros ever had, and a powerful 300-year old dynasty was overthrown because of his insane actions. Bonus points for being killed by his bodyguard. The latter's reckless, childish cruelty and love of ordering executions resulted in a continent-wide civil war. Ironically if Joffrey's father actually was who he says he was he would be distantly related to Aerys, but Joffrey was actually fathered by his mother's twin brother.
Indeed, the whole Targaryen dynasty had this trope going on. Half of them were either good or competent rulers. The other half were Caligulas, with Aerys merely being the one who took it too far. Of Aerys' children, his son Rhaeger and daughter Daenerys are sane, while his other son Viserys is the next Caligula-to-be. The dynastic tradition of Brother-Sister Incest might have had something to do with this.
The Crackling Prince in Walter Jon Williams' Aristoi seems to qualify, although he never appears and is referred to only in discussing the past. He planned on "artistically" reconfiguring planetary landscapes with gravity generators —- with the people still living on them and expected to be grateful. Understandably "a commission had been formed in Perseopolis to examine his behavior", but he was somehow persuaded to retire before the other Aristoi actually did anything.
The ruling Urga line of Cthol Murgos in the Belgariadall reliably go insane before late middle age. Taur Urgas is said to execute people for stepping on his shadow and encourages his sons to kill each other so the strongest one could claim the throne; when the king of Algaria kills him, he turns completely animalistic in his death throes. Urgit, his successor in the Mallorean, survived to that point by stealing a key to the treasury and hiring assassins; he's actually sane, if a Deadpan Snarker, but that's because he's not Taur Urgas's son at all - his mother had an affair with Silk's father, and he was the result. Thankfully for Cthol Murgos, the Urga bloodline has died out.
Urgit does seem a bit unstable at first, though more flippant than bloodthirsty, but that is because he is very well aware of the 'all reliably go insane before late middle age' rule. If you know you'll descend into insanity soon enough, why bother? As soon as he learns why his mother is so insistent the Urga curse won't affect him, he quickly drops the flippancy and becomes an effective ruler.
There was King Gurnt the Stupid of Lancre, whose attempt at training an aerial attack force of armored ravens never got off the ground.
Duke Felmet, also of Lancre, might have been stable before he gained the throne through regicide, but afterwards he would regularly try to remove the blood from his hands via sandpaper or cheese grater and be surprised that this only generated more.
Ankh-Morpork has had its share of unbalanced rulers as well, like King Ludwig the Tree, who once issued a royal proclamation on the need to develop a new type of frog and thought up the city motto "Quanti Canicula Ille In Fenestra" (which is pseudo-Latin for "How much is that doggy in the window?"), and King Lorenzo the Kind, who was "very fond of children". King Lorenzo was the last straw; after his execution, Ankh-Morpork became a republic, led by the Patrician — although actually it was more like the nobles appointed one of their number to wield power. By the time of the books, the Council chooses the Patrician and includes nobles and Guild leaders. Safe to say there is no electing in the modern sense going on. Some of the Patricians weren't much better:
Homicidal Lord Winder turned Ankh-Morpork into a police state out of paranoia.
The aptly named Psychoneurotic (sometimes merely Mad) Lord Snapcase — who, in a Shout-Out to Caligula, made his horse a councilor. (Although it apparently wasn't a bad one compared to the others: a vase, a heap of sand, and three people who had been beheaded.)
The Agatean Emperor in Interesting Times, who is liable to order people tortured to death or rewarded based upon the slightest whim (since no one ever dared to tell him that this is wrong).
In Raymond Feist's Riftwar series, King Rodric IV descended into insanity as the Riftwar proceeded. Subverted at the end of his reign, when the blow to his head that eventually killed him also released him from his lunacy sufficiently to allow him to appoint a good successor.
They've also had Prince Serg, who would certainly have qualified, had he not... conveniently died... before succeeding to the throne.
Also, there is a widely-mentioned historical case where a Count Vortala did appoint his horse, Midnight, as his heir, but there is no indication that Vortala was either crazy, or evil. He just did it as a Take That to his previous heir, whom he was having an argument with.
Specifically, "If a horse's ass can be a Count, why not the whole horse?"
At least as portrayed in the 1632 series, Charles I of England seems to qualify. The Stuart monarchs in general were firm believers in the divine right of kings; they were also generally pretty feckless as rulers. 1632 Charles has heard what will happen to him and is lashing out at his future enemies. True to form, he's messing it up (he's driven his historical best supporter into working with Cromwell, who's still alive, if on the run). Odds are the English Civil will come early in this world. This makes him a particularly incompetent Caligula.
This is a concern raised about Maeve in The Dresden Files: Cold Days. If her mother Mab is killed, then Maeve will inherit the mantle of Queen of Winter. Harry begins to realize just how bad this would be when he starts learning more about Mab's job: The Winter Court's army outnumbers that of the Summer Court by a huge margin, and could probably take over all of Faerie if their Queen willed it. However, the vast majority of Winter's troops are stationed at the Outer Gates, where they are constantly holding off a siege by the Outsiders. If the Outsider army ever got in, they'd destroy reality, and Mab isn't crazy enough to sacrifice reality in favor of her own personal goals. Maeve, however, probably is.
Mad King Alan II in Stephen King's The Eyes of The Dragon is a good example of this, although his madness tended more towards harmless debauchery. It was only through the malevolent influence of the story's Big Bad that he inflicted genuine suffering on the populace.
Randall Flagg from The Stand barely remembers most of his own life, is prone to childish fits of anger, and doesn't even seem to understand his own motivations; he just seems driven by some instinct or outside force to cause as much mayhem and destruction as he possibly can. And he may or may not be the devil.
In Barry Hughart's Bridge of Birds The Story of the Stone, the infamous Laughing Prince committed all sorts of horrors on the peasants in his valley, some of them in pursuit of immortality, some just because he was crazy. He was named for his cheerful, laughing demeanor and charming little dance step. Li Kao diagnoses him as brain-damaged from repeated consumption of a mercury-laced "elixir of life."
In Dragon Age: The Stolen Throne, the Orlesian usurper Meghren, who is given control of Ferelden by The Emperor, really hates being stuck in this "backwater" part of the Orlesian Empire. As such, he forces the Ferelden nobles to go out of their way to please him... and then randomly executes a few just for kicks. He doesn't care about ruling the land and only wants to get back into the Emperor's good graces so that he will be allowed to return to the Orlesian capital.
Julian: Gallus was always a bit of a sociopath, but he goes downhill fast once made Caesar. Libanius comments that much of what he did copied Caligula and Nero, as if he deliberately studied Roman history to find new atrocities to commit.
Terror the mastiff mix from Survivors cruelly beats up the dogs in his own pack for even the slightest hint of doubt about him and the "Fear Dog". It's soon revealed that the pack will fight for Terror because they're scared of him. But once Lick kills him, a new leader rises in his place: Twitch.
The Age of Fire series has SiDrakkon, a lazy and hedonistic dragon never gets off his tailvent unless it's to fight. When he eventually becomes Tyr, his refusal to actually do anything related to leadership brings the Lavadome to the brink of civil war, and the last time we see him before SiMevolant assassinates him, he's in his bath, ranting about how everything that isn't silver is corrupt and impure.
The Centauri Republic's insane emperor Cartagia from Babylon 5. He even sets his planet on a path he knows will probably end with it blown into little pieces because he thinks it'll make a fitting ceremony for his ascension to godhood. In the end, soon-to-be Prime Minister Londo and his associates assassinate him.
The new series' Master, who under the alias of Harold Saxon became Prime Minister, despite still being as mad as ever, if not more so.
John Simm had actually played Caligula in a made-for-TV miniseries in 2004, with copious amounts of ham(oh yes). Later, Simm has been quoted as saying that Caligula was just a dress rehearsal for the Master, and that he partially based his performance on Caligula.
The Doctor indulges in some Super Dickery by pretending to be this in "Invasion of Time", feigning power-madness and bullying his underlings into feeding him jelly babies.
Luke Rattigan in "The Sontaran Stratagem" and "The Poison Sky", who in addition to being an Insufferable Genius, is quickly revealed to be The Quisling conspiring with the Sontarans to wipe out humanity, with the sole exception of himself and a few chosen intellectuals who will serve as breeding stock as they colonise the planet "Castor 36", aka "Earth.2" or "Rattigan's World". His ultimate Heel-Face Turn only comes after the Sontarans reveal that they had no intention of honouring the deal and the planet itself never existed, leading him to teleport up to the ship with a bomb simply to spite them.
The Doctor: No-one's said "No" to you in a very long time, have they?
Monica Mancuso on Las Vegas. The Montecito's other owners have ranged from reasonable (Gavin Brunson) to friendly (Casey Manning) to aloof but thoughtful (AJ Cooper), but Mancuso gradually devolved into outright megalomania during her stay.
In the 1998 Merlin series, King Uther became this shortly before his death.
Peter Falk plays a thinly-disguised Expy of Fidel Castro in an episode of the original Twilight Zone that revolts against the previous ruler. Once in power, he becomes insanely paranoid and orders the executions of all of his former allies because he thinks they want to assassinate him. He finally flips out completely and commits suicide.
Wiseguy's Mel Profitt is a billionaire Arms Dealer and drug smuggler who suffers from bipolar disorder and severe paranoia. He's given to sudden manias (in one episode, he forces the protagonist to join him for batting practice at 3 o'clock in the morning so he can rant about his plans to buy an MLB franchise) and weird obsessions (he believes that everyone from Virginia is either a CIA or FBI agent, and has had people killed on that basis in the past). In the end, he completely self-destructs when he convinces himself that a Caribbean strongman he's in business with has put a voodoo hex on him.
In Stargate SG-1, the episode "Lifeboat" has Daniel accidentally end up sharing his body with multiple consciousnesses from a crashed ship. One of them is their ruling Sovereign, who definitely comes across as one of these.
The co-owners of "Amy's Baking Company" from Kitchen Nightmares to the point they have their own subsection in its Tropes page just to show how insane they are.
King Joffrey from Game of Thrones is an inbred sadist and an idiot who publicly murders babies and tortures/kills prostitutes and then wonders why everyone hates him in spite of being their king. The notion that people don't automatically love him is completely alien to him. He is also responsible for a civil war because he wanted to see Sean Bean 's character's head cut off. He also looks uncannily like the Mad Emperor himself.
"The Black Widow" by Alice Cooper describes a Caligula-esque figure, right down to having a cult of personality and implied sexual deviancy.
In the "Story of Evil" by mothy, Rilianne is initially depicted as this: she revels in luxury while her subjects are starving, and when the man she loves falls for a green-haired girl, she orders the death of all girls with green hair. Later songs and supplementary material make her a bit more morally nuanced: her selfish behaviour is largely caused by her acceding to the throne as an immature teenager, her murder of the green-haired women was because she was insane with jealousy, and she sincerely loves her twin brother who lets himself be executed in her place when she is deposed.
Guard Duck from Pearls Before Swine. During his brief reign as Mayor he used the city's funds to get revenge on his "enemies list", built a giant statue of himself, and saw All the President's Men as an instruction book on how to run the city.
Vince McMahon has been portrayed as the ultimate Caligula in Professional Wrestling. Like the phrase "Don't Cross The Boss". If you do, you might be forced into a handicap match with the Wrestling Monster and or Power Stable of the week, have to join Vince McMahon's 'Kiss My Ass' club or simply be told that "You're fired!!!!"
Eric Bischoff was WCW's Caligula, was WWE's Caligula when McMahon chose to step out of the spotlight, and is currently TNA's Caligula.
Triple H during the McMahon-Helmsley era and later during the Evolution era, and yet again with the Authority.
Recently Vickie Guerrero has been wrestling's number 1 Caligula. Cross her and you can kiss both your dignity and your balls goodbye.
AJ Lee had been thoroughly driven out of her mind by Daniel Bryan, so Vince McMahon decided to give her a stint as Raw's general manager, likely because he thought it would be funny or something. But TV Tropes wants you to know it never called her crazy because it would rather not wrestle Kane.
AJ might not belong here because whatever else you could say about her - that she's rude, annoying, manipulative, and not mentally fit to run a hot dog stand - it's a stretch to call her "evil." She's still clearly the face in all her altercations with heel characters, if not with fellow face characters, and is more a Psychopathic Womanchild than anything else. Instead, the Caligula figure here is once again Vince McMahon, who willingly put this will-o'-the-wisp in charge just to boost Monday Night Raw ratings.
Exalted: Anyone whose soul is affixed to the Exaltation will behave this way due to death-curse from the creator-gods they murdered, but Solar Exalted takes the proverbial cake.
Lord Konda, emperor of the greatest nation of Kamigawa. In his mad desire for immortality to rule his kingdom forever, he steals That Which Was Taken, which single-handedly begins the Kami war. The flavor texts of many cards paint a vivid picture of his descent into madness.
Lies spread by CommieMutantTraitors. Friend Computer is flawless and all-knowing, and works tirelessly to ensure the safety and well-being of all citizens of Alpha Complex. Will the citizen who wrote the above entry please report to the nearest Termination Booth. Further, all citizens who read this Commie Mutant Traitor propaganda are declared to be irreversibly contaminated, and are to report for termination at once. Please note, failure to report for termination is grounds for immediate termination. Have a nice day-cycle!
Ravenloft loves this trope. About half the domains are ruled by Caligulas (even if they're not the actual dark lord). Some examples include Othmar Bolshnik, who's on the brink of declaring himself king of a nation that withholds the title of "king" for their mythical religious ruler; Ivan Dilisnya, a paranoid opera fanatic who sends suspected enemies, actors who displease him, and anyone else he has a problem with to his Play Room; and Vlad Drakov, who seems to be the creators' attempt to put Vlad the Impaler and Hitler in a blender and see what comes out.
The Sorcerer King Abalach-Re in Darksun is pretty obviously based on the actual Caligula
Traveller: Emperor Cleon III, the last known descendant of the Third Imperium's founder, was known for resolving disagreements within his cabinet by shooting the most vocal ones. Within a year he was assassinated by the Imperial Moot, who then codified the "Right of Assassination" in law.
Vampire: The Requiem: the Ventrue clan. While it's possible for other clans to go Caligula, 9 times out of 10 it's a Ventrue. This is because they not only have lordly instincts, but their clan weakness is a tendency to easily pick up Derangements if they fall down the Karma Meter. So if a Ventrue Prince has to make the hard choices, and is able to rationalize them away, the crazy's going to start to leak through sooner or later...
The Ventrue have dozens of bloodlines, all based on this concept. Just want to be a crazy? Try the Malkovians. Creepy obsessive shut-ins? Malocusians. Sadistic gluttons? Macellarius. Ventrue supremacists with overhanging racist/nativist tendencies? Deucalion. Crazed worshipers of divine architecture? The Architects of the Monolith. In fact, in a possible creation myth explained in Mythologies, Caligula was, in fact, the first Gangrel. Gaius Julius Caesar was the first Ventrue. Bullshit, yes,but a very clever Lampshade Hanging about the Julii clan.
More than a few planetary lords in Warhammer 40,000 probably fit into this category, but special mention must be made of High Lord Goge Vandire, who in the 36th millennium managed to take control of both the Imperium'sAdministratum and Ecclesiarchynote by means of first installing an incompetent and weak minded Ecclesiarch and then having him executed for being incompetent and weak willed before declaring himself Ecclesiarch, beginning the Reign of Blood. Vandire was notoriously paranoid and ordered the deaths of millions and the destruction of entire worlds due to real or imagined plots against him. He eventually developed a phobia of light and took to wandering the darkened corridors of the Imperial Palace while muttering to himself, and was ultimately killed by his all-female cadre of bodyguards to end the devastating civil war. In the four thousand years since then, the Imperium has all but destroyed itself waging penitent crusades to atone.
Werewolf: The Apocalypse had the Silver Fangs, the "ruling tribe" of werewolves, who, thanks to inbreeding with the royal houses of Europe, had an increasing tendency to be off their rockers.
Black Tooth, a Simba (werelion) king among the Bastet, was a brutal ruler who waged a genocidal campaign against the Ajaba (werehyenas).
BattleTech: At least one member of each of the Great Houses has played this role. The most infamous of them all is Stefan Amaris of House Amaris, who instigated the Amaris Coup and brought an end to the Star League. Most members of the Houses are known for being paranoid, sadistic and power hungry, and Stefan is the universe's equivalent of Hitler.
And in William Shakespeare's Macbeth, Malcolm describes himself as this to Macduff. Specifically, he claims that his appetites for wealth and women are insatiable, and he would dedicate all the blood and treasure of Scotland to satisfying his carnal, venal, and pointless urges. This is all a ruse; he is making these claims because he suspects Macduff is an agent of Macbeth, in which case Macduff would continue in his stated goal of bringing Malcolm back to Scotland to take the throne. As Macduff is a true loyal Scot, he is instead demoralized by Malcolm's revelations, at which point Malcolm reveals the truth and they form an alliance.
Macbeth himself, on the other hand, plays this much more straight. Visions, paranoia, and murder are all par for the course for him.
Vath from AdventureQuest Worlds. He enslaved the dwarves, making them work without food, water, or even weapons. He's a lousy dictator, believing that their weakness and hunger was fine with him and not even caring if they starve to death as long as they forge enough Chaos Gemeralds for him to use to hatch the Rock Roc.
Vath: Dwarves are a hearty breed. That is why I allowed them to live as my slaves. If a few die then we are just pruning the weak branches from the strong tree.
In the first Assassins Creed, Majd Addin is the Token Evil Teammate of the Templars, since while the rest are Well Intentioned Extremists, the better world they are striving for means nothing to him, only the rush of power and the kill. Probably best described by himself when confronted about his misdeeds:
"I killed them because I could. Because it was fun! Do you know what it feels like to determine another man's fate? And did you see the way the people cheered? The way they feared me? I was like a god!"
The cast of Blood Storm is nearly composed of megalomaniacs, all of them fighting to become the High Emperor and thus be true Caligulas. Take your pick: the pyromaniac warlord, the ice-blooded king with a superiority complex, a Hive Mind that tortures people for fun, an Amazon hoping to eliminate the entire male gender, the radioactive mutant that intrudes on the contest, the vengeance-obsessed cyborg smuggler, or the spoiled princess/assassin. The only good character enters the contest to get everyone to stop listening to the paranoid nuts and actually start fixing the planet.
King K. Rool from Donkey Kong Country. It got so bad that apparently his minions deposed him and replaced him with a robot. Then you find out later that he was controlling the robot anyway...
Dwarf Fortress: dwarf nobles have a tendency to sentence dwarves to "hammerings" (usually fatal, but not always) when their mandates are not met.
King Zephiel in FE6 is pretty far off the handle, too. After all, the most seriously disturbing facial expression in FE7 is Zephiel's mad gaze at the end of the epilogue...and this is a game whose Big Bad has a Mad Eye with a nasty scar over it. Yeah, he's seriously wacked... and the saddest thing is that he wasn't always like that.
Final Fantasy VI: Kefka! He was already stark raving nuts when he was serving as the Emperor's Dragon. But when he got hold of the power of the gods and bumped off the Emperor, hegotevenworse.
Mad King Ashnard, Social Darwinist villain of Fire Emblem: Path of Radiance. In order to be crowned king, he orchestrated a plague that wiped out a large amount of his country's population to get rid of the many nobles who were ahead of him in the line of succession. Notable for attempting to start a worldwide conflict and release a dark god on the world just because he felt like it. After touching an amulet that was established to drive most humans into a mindless killing rage, his personality remained unchanged, the implication being that he couldn't possibly become any worse than he already was. Interestingly enough, he wasn't considered to be a bad ruler by the common people of Daein, largely due to his policy of awarding high-level positions to anyone of sufficient skill.
Mortal Kombat's Shao Kahn. He cares nothing but holding absolute power, driven by an ambition based solely on ego and a lust for conquest and power. He even promoted infighting and competition amongst his minions in a "divide and rule" policy to the point where the Centaur and Shokan races went to war with one another to curry his favor (and thus gain more power), and as long as he holds absolute power he doesn't really care about laws beyond "what Shao Kahn feels like" and how his people live their day to day lives, though it tends to be pretty miserable, desperate and violent thanks to how sadistic and brutish he is.
Halo's Covenant Prophets tend to fall in this category, especially the main trio. They know the whole Covenant thing is a load of crap. They just want to genocide humans because the humans are inheritors of the Forerunners, and proof that the Forerunners were physical beings and thus proof that their religion is all lies. Truth really stands out, by the end he's clearly a complete psychopath. The canon scientific name for the Prophet species is Latin for "Worms of Treachery." Also, what the main three Prophets are Prophets ''of'':
The Prophet of Truth is a blackmailer. He blackmailed the other two into take power alongside him, and blackmailed his way into power in the first place. He's also a Consummate Liar and a total psychopath.
The Prophet of Regret is a milquetoast who regrets an affair and being blackmailed by the Prophet of Truth.
The Prophet of Mercy is a psychopath who killed his own lover when she got pregnant, because having a child right then would be politically inconvenient.
In the back story to the Homeworld series of RTS games, the Taiidani Empire fell under the control of a particularly... 'unstable' ruler, who then proceeded to compound the problem by massacring all his rivals and decreeing that all future Emperors would be clones of him. The insane policies 'he' carries out during the course of the game lead to the empire being overthrown after the insanely efficient Hiigaran fleet kills 'him'.
Mega Man Zero: The first game's Big Bad who made a recurrence in Zero 3, Copy-X, was intended to be a hero for Neo Arcadia in place of X and is esteemed as such by the humans, who believe that he is the original X.
Also, in the same series, we have Dr. Weil (the Bigger Bad of the entire series) in Zero 3 and 4, known in history for starting the Elf War, which resulted in the annihilation of a large percentage of humans and reploids and the creation of the Crapsack World the series takes place in, and he's incredibly insane. This resulted in him being sentenced to exile in the wastelands he created in an undying mechanical body. Once he succeeded the Neo Arcadia throne after sabotaging Copy X Mk. II and blaming it on Zero, he started to oppress both Reploids and humans because he believed they deserved to be punished for banishing him out into the world he created. It got so bad that in Zero 4, some human refugees (who were brave enough) fled from Neo Arcadia to get away from him, and Weil retaliated by attempting to destroy Area Zero, - the only other habitable place left on Earth - forcing all humans to live under his oppression. Even his Dragon, Craft, realized how insane he was that he fired Ragnarok on Neo Arcadia in a (failed) attempt to kill Weil.
Porky Minch from MOTHER 3. He passes himself off as a great hero, despite corrupting the once vibrant world into an industrial wasteland, and using anything and anyone he can get his hands on as his personal playthings. At the end, he reveals his plans to awaken the Dark Dragon and destroy what is left of civilization, all for a quick laugh.
Radiant Historia's King Victor was by all accounts pretty bad, to the point that his son and his brother actively rebelled against him, but he has nothing on the stuff his second wife pulled once she gained the throne. Queen Protea managed in only a few years to turn the country into a police state where dead bodies littering the alleys are a common sight and half the population is starving to death, while she spends her time lounging around the palace and ogling choir boys. Then, when La Résistance gets uppity, she has the entire city lit on fire.
Yggdrasil in Tales of Symphonia: Because his sister was killed, he's striving for an age of lifeless beings, thus misinterpreting his sister's wish of a world freed of discrimination and tyrannizing the world. Even when his own sister - temporarily resurrected - tells him how wrong his plans are, he refuses to listen, thinking she's rejecting him, and simply goes crazy.
A somewhat more humorous example of the trope is referenced in The Elder Scrolls IV: Oblivion's back story, detailed in the in-game book The Madness of Pelagius. Pelagius was given an amulet that drained his sanity over the years. Early on, his weight would shift alarmingly from overweight to anorexic. He was known to have locked foreign princes and princesses in his room with him until their countries threatened to wage war, but his madness became much more noticeable when he stripped naked during a speech. This was before being crowned emperor. When an Argonian diplomat came to Tamriel, Pelagius insisted on speaking in what he believed to be its "natural language:" Grunts and squeaks. The book mentions him ordering his servants to clean the palace early in the morning; he is said to have defecated upon the floor to give them something to do, but this is described as "probably apocryphal." After he began to bite and attack visitors to the palace, he was moved to an asylum, his last act on Earth being to outlaw death. On his deathbed. This is a borderline example, since he didn't actually rule the empire.
The Elder Scrolls also has Sheogorath, appropriately the god of madness. He features heavily in Oblivion's Expansion Pack, where the player can visit his realm. Though not nearly as dangerous or unpredictable as other Caligulas, Sheogorath does have his eccentricities, including going into a rant about cheese while briefing his champion on a mission, making burning dogs fall from the sky, alternating randomly between happy and violently threatening, and having a Split Personality: the expansion pack's Big Bad.
He is also implied to have several personalities and random, semi-frequent bouts of more specific neuroses, such as hypochondria. And anyone who grows facial hair is to be executed. Because only the Lord Sheogorath is allowed to grow a beard, obviously.
Zant from The Legend of Zelda: Twilight Princess plays this trope to a T. After forcing Midna into exile, he proclaimed himself the new ruler of the Twili, only to be soundly rejected by them. Being the power hungry man that he is, he didn't take it well, and turned to Ganondorf in order to enslave his own people against their will.
Viva Caligula from the Adult Swim web site is built around being a crazy tyrant and killing everyone you meet in creatively horrible ways.
Lord Dimwit Flathead, the most well-known (and infamous) ruler of the Great Underground Empire in the Zork series, was particularly known for his excess - a coronation ceremony that took thirteen years to organize and carry out, the 3000-gated Flood Control Dam #3 (which served absolutely no purpose whatsoever), the creation of a subterranean desert mountain in a cave below his castle, and a 98% tax rate (and on the day of his death he proposed to adopt all his subjects and cut off their allowance to raise taxes to 100%) instituted to pay for such grand civic works. His last work was to be the creation of a new continent shaped in his likeness. Fortunately for mapmakers, he died before the project could be started.
King Leoric of Khanduras from the Diablo series was once a just and noble king, but was driven mad by Diablo's attempt to take him over. When his Evil Chancellor, Archbishop Lazarus, kidnapped his youngest son Albrecht to be made a vessel for Diablo, Leoric lost it completely and fell into this trope's territory, having many people tortured and executed, up to and including his own queen, out of paranoia, an event that would come to be known in Tristram as "the Darkening." Leoric was slain by the captain of his army, Lachdanan, who could no longer bear to see his people suffer under his liege's madness. Unfortunately for Lachdanan, his knights, and Tristram, the story did not end there.
It's mentioned that the Grey Wardens were originally exiled from Ferelden after a failed coup lead by Warden-Commander Sophia Dryden against King Arland, when the other nobles begged her to depose him for being completely out of his mind. Avernus mentions having attended a feast where Arland nonchalantly presented the Teyrn of Highever's head on a platter, as a warning to the other rebellious nobles.
During the Arl of Redcliffe questline, Connor Guerrin has shades of this, due to being under the influence of a Desire Demon.
Vaughn Kendalls from the City Elf origin. A brutish, unrepentant rapist and murder, who's allowed to get away with terrorising the Elves in Denerim due to being the son of the local Arl. That is, until the City Elf finally has enough.
In the 2014 retelling he's even worse: now he's constantly speaking over the city's speakers to remind citizens of the punishment for crimes such as rebelling against Meio, fiddling with technology, breaking curfew, even disembarking slowly from the subway. Most notably, he spent a huge sum of money and resources in building a giant Cool Tank that's Awesome, but Impractical, since no one except himself can actually drive it. And why he build it? Because he wanted one for his collection of weaponry.
Emperor Vorios the False, AKA the Mad Emperor from WildStar. Managed to drive this universe's version of Rome into the toilet—and the Dominion was complete with unstoppable military force, wide-reaching territory, and almost infinite resources!
Gilgamesh in Fate/stay night. Sofreakingbad. The prequel reveals that he's so batshit crazy irresponsible that he might as well be a Starfish Alien as far as Saber is concerned. And as in the original epic also royally pissed off his own people when he invoked Droit du Seigneur on the women of his kingdom, to the point that the Gods answered their prayers in the form of Enkidu, who beat the snot out of him before they eventually became friends.
Saber's kingdom collapsed because of this popular perception of her. Saber tried to become the perfect king, ruling fairly and without hesitation while mercilessly crushing any enemy, even if it required the sacrifice of some villages. While her most trusted knights believed she was a good king, her apparent lack of emotion and compassion alienated most of her subjects and resulted in multiple civil wars.
Makihisa Tohno of Tsukihime was the head of a major business but also deeply troubled due to his demonic blood causing bipolar disorder and schizophrenia. Every girl in his manor has deep psychological scars from differing forms of abuse while Shiki is the last survivor of the Nanaya clan, kidnapped and mind-wiped into being a member of the Tohno clan on Makihisa's whim.
King Steve from 8-Bit Theater is a Black ComedyCloud Cuckoo Lander. One of the least dangerous things he has done was betting the office of King in a poker game. He lost the game to a piece of string..."whom" he then assassinated by cutting it in two with scissors when no one else was near.
Black Comedy as babies are what his shoes are made of. They tend to rot, however, so he has to get new ones "Fresh daily."
One if his frequent "elections" simply gave the population the choice of either King Steve as supreme ruler, or to get a sword in the head. 52% of the survey population died.
Another time, he set up a snow cone stand. This might sound mundane at first, but the Light Warriors noticed something strange about the aforementioned snow-cones, leading to this exchange:
Black Mage: What is this?
King Steve: It's no cone!
Thief: It's a cube.
King Steve: Oh, no. That's a common misconception. It's a stube.
He also thinks that he invented inventing, started a war to force pacifism on the elves, and was once told he had news and enthusiastically asked "does it involve cupcakes?" and decided he didn't care when the answer was no, thinks he designed his castle to be four hundred years old, and apparently knew what a robot version of himself was saying even after the robot exploded. If he isn't a ditz then nobody is. Did we mention that he is unable to tell the difference between his daughter and his Beleaguered Assistant Left-Hand-Man Gary? (In case you were wondering, his right-hand-man is a coffee stain called Rodney.)
Chancellor Valorum in Darths & Droids. The annotation explains that they wanted to make him more interesting than in the movie version, who was bland and boring. Consequently, he becomes a maniac who praises the droid army for overthrowing their human oppressors, urges people to replace their bodies with cyborgs, and demands that all shall "Kneel BeforeValorum!". His getting voted out of office makes a lot more sense now.
And he turned out to be General Grievous. It makes so much sense.
Kharla'ggen Vel'Vlozress of Drowtales is extremely insane, and has a hobby of turning living peopleinto living dolls and altogether has the mental capacity of a young child and no real sense of morality. Despite this she does get a few Pet the Dog moments with her adopted sister, Kiel'ndia (who, despite Kharla being the one who turned her mother into a puppet, seems to get that Kharla doesn't really understand and thus doesn't blame her) and it's suggested that if left alone she wouldn't be so bad.
Among the Sharen clan, all of whom could qualify at some level, Sarv'swati Vel'Sharen develops into this over the course of the story. It's not so much that she's crazy like Kharla so much as extremely brutal, exerting what her own sisters call "maniacal" control over her family to the point that after her sister Sil'lice was exiled she executed members of her own family for sympathizing with her, and brutally executes one of her own relatives after fails her for the last time. She also was part of a plot to kill her own mother, and was the one who sealed the deal by sealing her in her throne room to die, and covered it up by using a Body Double for public funtion and masterminds the idea of Dari'yako, a Penal Colony where commoners are sent, and her use of a slave army made of conscripted commoners that turns most of the population against her.
To quote from Zhor, Snadhya'rune is the truly rightful heir to the empire of the entire Drow race, and would be the undisputed ruler were she not completely insane. Her latest plan involves poisoning her enemies with a lethal fungal disease, and evolving the fungus so that the only ones who can survive the disease are tainted. Her ultimate goal is to TAINTEVERYONEALIVE. And she uses speech craft and her own insanity to pose this as a good thing, right in front of her entire collection of potential allies, all while using one of her minion's Compelling Voice powers to make everyone Kneel Before Zod apparently just for the ego trip.
Eridan Ampora (aka "caligulasAquarium") from Homestuck is a number of the royal sea-dwelling troll caste. His primary interests revolve around genocide of the land-dwellers and his many failed efforts at romance. He mostly embodies this trope in his blind self-absorption and poor decision making until his Face-Heel Turn.
A better example of this trope, oddly enough, is the Grand Highblood, Gamzee's Ancestor, who brutally terrorizes the other, lower land-dwelling castes through capricious homicide and psychic nightmares in the name of his Monster Clown religion. However, this is characteristic of the Subjugglator caste as a whole and not a one-off thing.
The biggest Caligula so far is Her Imperious Condescension, who in her home universe spent her time flying to new civilizations and meeting with them peacefully before blasting them to smithereens. And then after her empire is destroyed by The Vast Glub enters into the service of Lord English and goes to the B2 Earth, where she goes mad as the result of repeated botched attempts to recreate her old empire "in all its convoluted symbiotic glory." She ends up taking out her frustrations on humankind, by trying to bioengineer them to have troll blood colors and outlawing sex because she finds it squicky, so by the time Dirk and Roxy are alive 400 years later humanity is extinct.
The Law of Purple: Silver is the king of a planet called Caligula and yes, he's a very bad king.
Richard from Looking for Group seems to be this with the town he is mayor of. However his citizens don't mind it since they are already dead.
Implied in an Oglaf strip where two princes have been forced into arranged marriages by their father... with a pig and a withered corpse. One prince comments that there should be a rule that you should be forced to abdicate the throne when you start doing things like that.
Christian Weston Chandler plays this trope to the hilt as the Mayor of CWCville in Sonichu. He enacts all sorts of bizarre laws that treat smoking as being as heinous as rape and murder, he brutally slaughters anyone who tries to stop him from doing whatever he wants, and his will is enforced by what is essentially a multicolored hedgehog Gestapo who according to Word of God enjoy full immunity from the law. His civic policy decisions are equally as insane-in Sonichu: The Animated Series, he ordered that the CWCville waterworks circulate orange soda pop instead of water, which leads to fires continually breaking out all over the city.
The Baron in Spiky-Haired Dragon, Worthless Knight is as much of a Caligula as he can be without pissing off higher-level nobles and fellow barons, which is still a lot, especially to the title character (the knight, not the dragon).
Stephen in Terror Island, who somehow managed to be elected Czar of Geography City, largely wields his power to sentence innocent people to indentured labor at Jame's restaurant and to attempt to force Sid to buy groceries. His successor Blueteen isn't much better, sending people to prison (including himself) for attending parades. Not only that, but the parade was actually only supposed to be for stuntmen. Why? Because he had just solved the problem of Jame's stuntman no longer being bound by law to him for jaywalking by telling Jame to just hire him.
King Jeffrey in Dragomirs Diary is a moody, capricious, fickle ruler who constantly changes the laws in his castle to suit his bizarre whims. Jeffrey is enough of a jerk that the only visible path into his castle, a bridge called the Neck, has been rigged with a horrifying buzzsaw trap that will cut up anybody he deems dangerous - but because the Neck is constantly clogged with guts, it tends to go off whether Jeffrey wants it to or not. Yet he won't have it removed...
A milder Caligula appears in v2 of Open Blue, Count Marcus Veneto, who even made his horse his war advisor, in a Shout-Out to the Trope Namer. The 'milder' comes from the fact that he's trying to get his act together. It's implied that this change of heart is the result of Men In Black being sent by two allied empires to intimidate him into doing so. Suffice to say, that hasn't stopped him from requesting an Amazon Brigade for his personal guard and naming them the Killer Bunny Assassination Squad.
When he couldn't go to Gamelon 'for the hell of it', spent the rest of the day saying 'Mah boi' over and over again.
Ask King Sombra presents Sombra as this instead of his depictionin the show. He's pretty dang nuts. In fact, most of the occurrences in the blog are simply him hallucinating after his defeat at the hooves of the mane six, which reduced him to a horn (Coffee Talk is trapped with him). Except the the ghost monster. That was actually Luna. His Enemy Within, however, is pretty much how he was depicted in the show proper.
Adventure Time has Xergiok and Lemongrab. Xergiok is a sadistic, cruel, jerkass leader who delights in spanking his subjects and intimidating them. Lemongrab is a bit of a more sympathetic example—he isn't evil, but he certainly is inexperienced (at being a ruler, AND at being alive) and has anger issues, which eventually leads to everyone in the candy kingdom being sent to the dungeon.
It doesn't help that Ozai made himself the Phoenix King when he crowned Azula, effectively making her position as Fire Lord meaningless. So while she would rule the Fire Nation, Ozai would rule the world.
The Earth Queen from The Legend of Korra undoes all the good things her father from the previous series has done for Ba Sing Se. Stuff she does include overtaking her people so that they lived in squalor while she lives in luxury and raising an airbending army by imprisoning them.
The Almighty Tallest of Invader Zim have tendencies as such, being perfectly happy to put their subjects under such events as Probing Day, where they make Invaders do ridiculous things to entertain them or else suffer a pummeling (pushing some buttons that lead to said Invaders getting beat up by their own technology). The entire principle of destroying a planet to build a parking garage or food court also says something about them.
They also tried to kill their best invader just for being shortnote and ugly. They order everyone to retreat from battle just because of their snacks being lost, and once even punished someone by shooting them out of the airlock. Security threw out the wrong person by accident. Their response? Apathy.
Tallest Purple: That was the wrong guy, but... it's okay. I think everyone gets the point.
Lucius Heinous VII on Jimmy Two-Shoes, who is primarily concerned with making sure everyone under his reign is Miserable. Special mention goes to one episode where he casually orders the destruction of one of Miseryville's suns because he felt that three was too many.
A tame example occurs in the My Little Pony: Friendship Is Magic episode "Hearth's Warming Eve". Pinkie Pie's character in the pageant about the foundation of Equestria is Chancellor Puddinghead, leader of the earth pony tribe and clearly a few apples short of a bushel. She was apparently an elected official, but it's a bit of a mystery why anyone would vote for her; it's possible that the various hardships brought about by the extended winter drove the earth ponies to desperation, as hinted at by the quote below.
Puddinghead: I was elected because I know how to think outside the box, which means - *shoves head up a nearby chimney* - I can think inside the chimney! *beat* Can you think inside a chimney?
In her second appearance Trixie becomes this thanks to an Artifact of Doom, turning Ponyville into an empire without Celestia (who at the time was performing royal duties in a far-off location) there to stop her. It was also making her more insane by the moment, to the point she spent half the episode being pulled around in a chariot without wheels because she didn't trust wheels.
Canon Princess Celestia is a wise and reasonable ruler, with just a few trickster shades. Fanon tends to exaggerate those shades out of proportion. The result is Princess Trollestia, who falls squarely into this trope. The best known example is probably the flash Friendship Is Magic Bitch.
Nero appears in an episode of Garfield and Friends, where Garfield tells the story of the cat who invented lasagna. In the story, Nero is depicted as a Villainous Glutton who imprisons (or in some cases, executes) bad chefs. When the cat's owner (the cat and the owner being Expys of Garfield and Jon) is thrown in prison, the cat appeals to the Emperor's appetite, claiming Jon is an excellent chef (even though he isn't) which persuades the Emperor to give him a chance. The cat's idea is that cats and emperors are very much alike, lazy, greedy people who like to be waited on, so he figured the Emperor would like what he likes, and directs his owner to make what is eventually called lasagna. It works; the Emperor loves it, and pardons the man.
The Sponge Bob Square Pants special "Whatever Happened to SpongeBob?" has an amnesiac SpongeBob finding himself in a city under the tyranny of a greaser gang who outlawed bubbles just because they have the potential to cause harm. In the end they turn out to have been Properly Paranoid when the city (somehow) collapses into chaos only a few hours after SpongeBob's bubble laws were put into practice.
Galvatron from Transformers Generation 1. Spending the time between the movie and season three in a lava pit turned him from the Megatron-but-competent of the movie to... uh... the way we all remember him being. He blasted more of his own troops in his rages than Autobots in battle, and at one point, some other Decepticons told his right hand bot Cyclonus that if something didn't change, they were going to deal with both of them. Too bad no Decepticon civil war ever materialized.
Straxus from the comics is even worse. His Animated counterpart, however, is played for laughs on a fan-run formspring page.