Somehow I manage to find cover and what does Baron von Ruthless do? [...] He starts monologuing! He starts like, this prepared speech about how "feeble" I am compared to him, how "inevitable" my defeat is, how "the world will soon be his!", yadda yadda yadda. [...] I mean, the guy has me on a platter and he won't shut up!
"I am Kira." Just so he could see the look on Naomi Misora's face moments before his Artifact of Doom kicked in.
Light also gloats evilly at the end of the penultimate episode. While it wouldn't have changed the outcome had he not done so, it was pretty reckless of him, and he only did it as a matter of pride to show how confident he was that he had successfully tied up all remaining loose ends.
The look on his face when L dies.
And then in the manga Light gloats one last time when he thinks Ryuk is writing his enemies names down.It backfires badly.
Averted hilariously in episode 5 of the first season of Birdy the Mighty: Decode, in which Birdy punches Kinzel's mecha, the Amubis 777 (yes, like Anubis) in the middle of his explanation of why it is so awesome and will own her (to which he responds, "You oughta listen until I'm finished!").
While the manga and anime adaption of Chrono Crusade disagree on quite a few things, there's one thing on which they agree: Aionloves to gloat.
When Tomoe confronts Arika in Mai-Otome after acquiring her new battle suit, she wastes no time bragging about her involvement in Miya's disappearance, Erstin's leg injury, and Arika's costume damage right before she and three of her companions attack. However, she was only supposed to capture Mashiro and get back to base as quickly as possible to avoid drawing attention.
In both the anime and manga versions of Bleach, the 9th Espada, Aaroniero Arruruerie, fights Rukia, breaks her sword, and skewers her with his trident. He pulls her closer so that he can gloat effectively. This is when Rukia pulls out her third Shikai which reforms her sword through Aaroniero's head instantly killing him. Sure, Rukia's sword reforming and her subsequent rescuing are major Deus Ex Machinas, but in Bleach, we lost count long ago anyway.
And that's not even going into Sousuke Aizen, who just loves to listen to himself talk, going by the fact that he has on a few occasions taken the time to fill the good guys in on every little detail regarding exactly how bad he's screwed them over.
To be fair to his villainous willpower, he will wait years for the opportunity for these gloatings. His first monologue was stored up over well over a hundred years of playing the nice guy. Of course, he did get to let it out sometimes, so long as he was sure whoever it was was about to die. Letting Urahara and Shinji and company get away alive bit him hard in future.
In the recent Fullbring arc, Giriko breaks into this when Drunk with Power...which gets him killed by Kenpachi.
Jail: Mid-Childa Ground TSAB members, did you like it?
Mahou Sensei Negima! has Chao doing this to Negi's friends after sending them a week into the future when she'd already won the battle by sticking a note gloating about her victory on the side of Eva's resort.
Evangeline is also fond of evil gloating, especially when she isn't doing anything evil. She probably wants to remind everyone she most definitely has not gone soft.
[A] Keep an eye on them to make certain they don't do stupid shit or have a game plan if they do?
[B] Sit there and go into full-on gloating as your shark's teeth pop back out?
or [C] have your summoned pets knock the last remnants of air out of them just to be sure?
If you picked B, congratulations, Ark! You just won an ass-kicking from Sapphire, who used those teeth to cut open the glass and drain all the water while you were gloating! Enjoy your dirt nap, sucker!
In the Liar Game, everyone does this after they believe they have successfully tricked their opponents, particularly if it was the protagonists Nao and Akiyama. However they are usually Out-Gambitted seconds later in a humilating defeat.
Frankly, this is a pretty common behavior of the homunculi, due to their massive arrogance. Greed and Lust both did Explaining Your Power to the Enemy (the latter because she didn't plan to leave them alive anyway), Wrath often monologues about humans being weak, and Pride is a Smug Snake because of his habit of threatening people and bragging about his superiority.
Unlike most examples of Explaining Your Power to the Enemy, they didn't really say anything that could make the good guys pick up on a weakness. They had to figure that stuff out on their own.
In the first season of Zero no Tsukaima, Cromwell, the villain behind it all, starts to gloat about how he'll never be defeated as long as he has the ring. Before he can finish the sentence, Guiche sneaks up behind him and hits him on the head with a big stick. "So, who is this guy?"
Despite being a very intelligent and shrewd man, Kabuto Yakushi from Naruto has a terrible habit of gloating before fallen enemies when he thinks (and usually does) he has the upper hand in a battle.
A good example is when he fought Tsunade in order to "convince" her to heal Orochimaru's soulless arms. He began kicking her while she was in her hemophobia-trauma-shock and taunting her for "bringing shame to the name of Sannin. Which Orochimaru has brought glory and power to!" (or something along those lines).
He also seems to do this whenever he and Naruto manage to meet up in battle. Since Naruto has a short fuse on anything involving Sasuke, it's not even a challenge to get him riled up by Kabuto's taunts.
Hidan is very good at this, which greatly annoy his partner Kakuzu.
In Hellsing, Zorin Blitz really likes doing this. However, it proves to be her undoing when she calls Pip Bernadotte an 'insect' and mocks him and the Wild Geese, while a blind and mutilated Seras is crying over his body. Understandably, Seras doesn't take it very well. To the extent that she paints the walls with Zorin's head.
In Haruhi Suzumiya, Ryoko Asakura does this when she attempts to kill Kyon so she can watch Haruhi's reactions. She was literally a second away from killing Kyon when Yuki saved him. If Ryoko hadn't taken the time to explain why she wanted Kyon dead, she presumably could have killed him before Yuki even arrived.
Ladd: And therefore, as such, in light of that revelation, I'll say that one is enough, and since that one is of course myself, I want you all to shut up. You're boring. Swallow those words and take them to the afterlife yourself if you want them delivered there so damn much."
Watchmen plays this straight, but with a nod to the oft-fatal habit of monologuing, but adds the already infamous twist to the end. When confronted by Rorschach and Night Owl, Ozymandias coolly explains his master plan to them. The heroes expect to be able to stop him yet, but he bluntly tells them his plan is already complete.
In the pages of Grant Morrison's JLA, the Key rants (basically to no one, since only his nonsentient robots are around to hear him) for about a page about how brilliant he's made himself through the use of brain-altering chemicals, and how it's allowed him to finally beat the JLA. It ends with this immortal aside:
The Key: Oh, and make a note of an interesting side effect of my expanding consciousness. I can't stop talking to myself.
In All Fall Down, AIQ Squared lays out his entire scheme to the confused and outraged IQ Squared.
The Big Bad in the album about oil in Oklahoma (because Lucky Luke missed him with the last bullet, and he is going to kill him now). If he hadn't done it, he could've succeeded.
Smallville: Season 11. Lex Luthor could have learned all of Superman's secrets by merely keeping his mouth shut and letting his equipment do it's thing after secretly dosing Supes with radiation that allows his satellites can track his every move. But as soon as the satellite comes on line, Lex demonstrates it to Superman, in order to gloat about how screwed he is. And based on a comment he makes later in regards to increased Superman sightings, at the time Lex didn't even consider that Superman had a Secret Identity!
Lampshaded in My Little Pony: Friendship Is Magic (IDW). As Chrysalis begins to describe what will happen should the Mane 6 miss the deadline, a fillynapped Scootaloo blurts out that she's about to reveal her evil plan to the heroines. Annoyed at the interruption, Chrysalis cuts off communication.
In the Jackie Chan Adventures fic Queen Of All Oni, Jade sometimes lapses into this, but is aware of it, being the Dangerously Genre Savvy villain that she is, and tries to avoid it most of the time. Finn, Valmont, and some other characters also do this at multiple times throughout the story, and it usually doesn't turn out well for them.
Later, after the Titans have put Forrester back on a hard drive.
Nightwing: Jericho, come in...Good news, Forrester cleared you with a villain monologue so the door on the van is unlocked now.
Subverted i In the My Little Pony Friendship Is Magic fanfic Envy And Arrogance. Arrogance soundly trashes the mane six and their allies. Then she launches into a long Evil Gloating monologue, which lets them recover and focus their powers. The subversion comes from the fact that she is quite obviously doing this on purpose - as she has outright stated that her boss' Xanatos Gambit will work better if they win.
Discord: “Enjoying your walk, Heartstrings? You’re getting along quite well on just two legs, I see. Like any other human. You really are one of them, aren’t you? I just wanted to stop by and offer my most sincere gratitude. If it weren’t for you, Heartstrings, I never would have found this place. And to imagine, you were right there in Ponyville the entire time! If I had known there were humans left, I wouldn’t have wasted my time there. No, humans are far more fun. I’m rather fond of humans myself. I suppose we have that much in common, you and me. All that technology, right? And their hands that they use it with?” Lyra: “W-where are you?” Discord: “Oh, I'm exactly where I want to be – here, in the human world. Can you imagine? A separate world, filled with millions of humans, and it’s been right next door all along. You’re really quite a lot of fun, you humans. And just look at how amazing this world is! Leave you alone for a couple thousand years and you accomplish all of this.” Lyra: “How did you get here? How did you find me? What are you doing?” Discord: “I think you know exactly what I’m planning. You see, I’ve been terribly bored, like you couldn’t even imagine. I’ve been in need of some good old-fashioned chaos. Or – my mistake – the humans here have all new ways to create chaos! I do look forward to this, I really mean that.” Lyra: “There’s more to humans than that. I’ve been studying them – us. We’re better than that.” Discord: “From the looks of things, you’ve all made quite enough chaos without my help. We’ll see about that. Well, I didn’t plan to visit for long. Just long enough to drop in and leave you with something. You see, there’s a whole world of humans out there waiting for me, and let’s just say you’ll be happier if you’re not one of them. Do you realize that there are billions of you in this world? Not thousands, not even millions. I could find millions of you in just one city. And it's not too far from here, is it? Like I said, Heartstrings – my sincerest thanks for your help.”
Atlas Strongest Tournament: When the changelings reveal themselves during the final match of the tournament, Aurelia goes into detail how they've been manipulating everyone in order to feed off of their skills and power, and will use it to conquer Equestria. Chrysalis sheds tears of pride on her artful delivery.
Lampshaded in Blaze: Into the Inferno when after capturing an initially reticent Bellatrix Lestrange Harry quipped "Real villains always explain their evil plots."
Lampshaded in Weres Harry when Harry commented to Riddle's shade "You're monologueing. That is what the bad guy does just before everything usually goes to shite."
Probably the one thing that defines Kaa of The Jungle Book as a villain rather than just a hungry predator is his gleeful tendency to play with his food. He would have surely eaten Mowgli if he hadn't extended the whole thing to a musical number.
In The Great Mouse Detective, Ratigan causes Basil to have a Heroic BSOD by gloating about how he led Basil right into his trap, then describing his overly complex Death Trap which includes a recording of Ratigan gloating through song.
Ursula does this in The Little Mermaid after she succeeds in hypnotizing Eric away from Ariel in her Vanessa guise. To her credit, she gloats only in the privacy of her room when Eric and Ariel aren't around but Scuttle still overhears her loud singing and is able to inform Ariel in time for them to crash her wedding to Eric.
At the end of The Lion King, when Simba, still blaming himself for his father's death, is dangling from the edge of a cliff, Scar can't resist doing some Evil Gloating and says "I killed Mufasa." Big mistake.
The LEGO Movie. Being such an overdramatic villain, you'd expect this from Lord Business. Specifically at the point where Emmet and his friends witness the death of Vitruvius at his own hands in the Think Tank, meaning now he is able to have his opponents at his mercy. But he isn't stupid to do this - none of them are able enough to take a shot at him. As in, all of the Master Builders have been imprisoned, Vitruvius is dead, Emmet is tied to the self-destruct mechanism's battery, Lord Business is armed to the teeth and not to mention his outfit makes it almost impossible to attack him. It doesn't do him any harm to gloat when everything's coming up great for him.
The Good, the Bad and the Ugly: a vengeful man catches up with Tuco ("the ugly" of the title) while Tuco is taking a bath. The pursuer starts ranting about tracking his quarry for weeks, and Tuco shoots him dead with the gun he has hidden under the soap-foam: "When you have to shoot.... shoot, don't talk!"
Khan: I deprive your ship of power, and when I swing around I will deprive you of your life! But first I wanted you to know who it was who had beaten you.
Near the end of Terminator Salvation, Skynet can't help but explain the genius of its master plan to one of its unwitting pawns and smugly gloat how it has used him for its own purposes and tells him to accept his newfound nature.
Ronan the Accuser, in Guardians of the Galaxy has a habit of doing this. It bites him on the ass at the end: by stopping to give a grandiose speech before annihilating Xandar he gives the Guardians enough time to improvise a plan to separate him from his planet-destroying MacGuffin.
The Red Baron in Blackadder goes forth does this. Subverted when Blackadder would rather be humiliated than die, lampshaded by Combat Pragmatist and all-round cad Lord Flasheart simply cries "what a poof!" and shoots him on the spot.
Ludwig also qualifies, as Blackadder says:
Blackadder: Typical master criminal; loves the sound of his own voice.
Done successfully by Londo Mollari in the Babylon 5 episode "The Rock Cried Out No Hiding Place" He explains to Lord Refa, via recording, his entire Evil Plan for no reason other than to grind Refa's face into his failure and imminent demise. Of course Refa is then horribly murdered by a mob of angry Narns and framed posthumously for treason, fulfilling the rant and the gambit both.
Ethan Rayne from Buffy the Vampire Slayer likes doing this. And its the only thing The First Evil ever really did, being intangible. Angelus was good at it too.
It's never a good idea to do this in the Buffyverse, however, as it tends to signal a villain's defeat, usually because speechifying leaves them open to attack or buys the hero time to recoil. Villains like Rayne are aware of this, but can't seem to help themselves: "I really got to learn to just do the damage and get out of town. It's the stay-and-gloat that gets me every time."
The First could pull this off because of the whole incorporeal thing. Though It was also an expert in Mind Rape
McKay: Hello, Anubis? Your agent called, you're playing it wayover the top."
And the Goa'uld wonder why the Tau'ri refuse to take them seriously.
Indeed, the only ruling Goa'uld they do take seriously are Lord Yu (who is too old and senile to ham it up that much), and Ba'al (who has learned how to be Affably Evil).
NCIS utilizes this often. One notable instance is in "Murder 2.0", which features a serial killer using a YouTube site to broadcast his murders, all in the name of fame. The killer proves to be a real headache for Gibbs, and when they're finally caught, this trope is utilized in their boasting that they would still be famous when their identity was revealed. Gibbs consequently ensures that, "citing possible links to terrorism", no details about the killer are released to the public.
Demons are the only type of evil at first the brothers face who pull this one. Occasionally some other malevolent beastie will indulge but every single demon does it when most creatures just get right to the killing, or at least attempted killing, of the brothers.
In the first season finale, the Yellow Eyed Demon does this. Dean lampshades it with "Just kill us, 'cuz I just can't take the monologuing." This just fuels the Demon's Breaking Speech.
Brady in particular gives one of the most disgusting ones in "The Devil You Know". While tied up, he gloatingly tells Sam how he manipulated him by possessing his friend back in college, and how much he enjoyed burning his girlfriend Jessica alive, setting Sam on the path to going back to hunting. It's so effective that Sam almost ruins the plan by killing him.
The villains in Castle often resort to this, sometimes because the evidence is so thin that it's necessary to have the murderer confess so the audience can be satisfied that Castle and Beckett have the right person.
Averted in Probable Cause. Someone frames Castle for murder. As Castle sits in a holding cell, they take the incredible risk of slipping into the police station to gloat. Except... it was all part of his plan to disappear. The Evil gloating gave Castle and Beckett the leads they needed to catch him, which was a necessary part of his Batman Gambit to be "killed" by Castle and Beckett.
In the episode of The Big Bang Theory entitled "The Vengeance Formulation," Sheldon makes foam fall on Kripke from the ceiling tiles in his office to get back at him. The plan goes horribly wrong when the president of the university and the board of directors are drenched with the foam too. Then, to make matters even worse, a pre-recorded video comes on to Kripke's monitor. It contains Sheldon gloating about the "classic prank" that Kripke has just fallen prey to. He also gives congratulations to Leonard and Raj for helping him with his plan.
Inverted in The West Wing when Secret Service agent Donovan is so busy gloating about how stupid a crook was to try to rob a store when the Secret Service was in town, that he doesn't notice the store clerk's very obvious eye rolling, trying to indicate that the guy he's caught has a partner.
Subverted at the end of the Doctor Who episode "Utopia", when Professor Yana transforms into the Master and begins to run away with the TARDIS. He says "Now, then, Doctor! Oooh, new voice. Hello, hellooo, helllloooo! Anyway... why don't we sit down and have a nice little chat where I can tell you all my plans and you can work out a way to stop me, I don't think!" Then he zooms back into the past leaving the Doctor, Martha Jones and Captain Jack at the End of the Universe.
The Daleks are prone to this, but do it to a noticeably greater extent with the Doctor than anyone else. In Asylum of the Daleks the Dalek prime minister suggests this is because they find the Doctor's hatred for them so beautiful that they can't bring themselves to destroy it, while in The Time of the Doctor the Doctor argues that they're always so frightened he has something up his sleeve that they don't dare just shoot.
"Boston" Rob Mariano had a tendency to do this on The Amazing Race, during pretty much every episode he was on, on both Seasons 7 and All-Stars, a carryover from his time on Survivor.
All My Children: After Michael Cambias is acquitted for raping Bianca, he takes the time to gloat to the entire courtroom that he "owns Pine Valley and everyone in it," which pisses everyone off so badly that Michael's attorney is warned to get him out of the building before the crowd decides to become a lynch mob. Unsurprisingly, Michael actually does turn up dead soon afterward.
In the season 1 finale of Lexx "Gigashadow", His Divine Shadow spends the last few minutes of the episode revealing his true nature and goals to the main characters. He taunts them with their failure to prevent his rebirth fueled by the sacrifice of nearly the entire population of the Light Universe and bids them extinction, capped off with an Evil Laugh. This causes his downfall since he's so busy gloating that he doesn't notice the baby Cluster Lizard Squish when it eats his brain.
A couple of times in minor Animorphs books, but most notably done by Tom's Yeerk in the final two books (narrated from different perspectives):
"You appear to be experiencing some engine trouble, Visser," Tom said, gloating.
<The Empire will track you down and kill you for this, you do understand that, I hope?> Visser One said.
"Oh, I doubt it," Tom said cheerfully. "The Andalite fleet is rather close by. It's possible that I misled you on that point." He was all but giggling.
Williams also pulls this in Memory, Sorrow, and Thorn in the part of Evil Sorcerer Pryrates, who spends half of the climactic chapter gleefully explaining his plans to the now-helpless protagonists so everyone involved will know exactly how thoroughly they failed to stop him. For bonus style points, he works some of it into the summoning ritual for the Storm King — and true to the trope, said villain promptly cuts off the gloating by demonstrating that Evil Is Not a Toy.
In Discworld this is a common feature of villains. Commander Vimes considers that an evil man always likes their enemy to know they've been beaten, thus giving them a chance to turn the tables, while if a good man feels he has to kill you, he'll do it with hardly a word.
Cats and witches also prefer an enemy who knows they're beaten. A key difference is that cats and witches know the dangers of monologuing, so they instead just make sure their opponent is so good and beat that there's no question.
Coraline gets out of the Other Mother's clutches by fake-guessing that her parents are hidden behind the door that leads out of the world, causing the beldam to open it so that she can gloat about Coraline being wrong.
In the Thursday Next novel The Eyre Affair, Big Bad Acheron Hades launches into a gloating soliloquy right when he has Thursday cornered. In the time it takes him to gloat, Thursday is able to figure out his one weakness (silver) and shoot him dead with a silver bullet.
In The Goose Girl by Shannon Hale, Selia gloats for a few PAGES about how she's a better princess, how Falada died, and so on, and how no one will believe poor Ani. She should have double checked behind the tapestries before she started...
Harry Potter villains just love this trope. Voldemort himself is easily the biggest offender, though nearly every major villainous character monologues at least once in the series.
Finally inverted with Harry himself monologuing Voldemort at the very end. Harry is in the lucky position of finally holding all the cards - to the point where it doesn't even matter that he tells Voldemort exactly how his shiny new weapon works.
I always took this as Harry telling the wand why it was his. After all, the wand was not present when Harry disarmed Draco. Unless they are omniscient, or there is some other way for it to tell, the wand may not have known until that moment that it belonged to Harry. Every other instance of odd behavior of wands was taken care of by other causes.
In "A Witch Shall Be Born", Salome opens the story with explaining her plot and her powers to her sister the queen and gloating over her.
Harry Dresdenfrequently notes the tendency of villains to do this, and thinks that it must be part of his training. He usually uses the opportunity to seize the initiative in combat, but sometimes is tempted to do the same himself, usually to his cost. For the immortals, it's somewhat justified since they live for so long that it can be easy to lose track of time spans less than a decade. The humans, though, are just stupid, arrogant jerks.
In Ghost Story, a villain actually uses this to their advantage -When she continually gloats about the situation in the middle of a fight with Dresden, he just thinks she's being stupid and attacks. He realizes a bit too late she was actually trying to trick him into Cast From Hit Pointing himself to death.
Subverted in Warp World: during Ethan and Jett's final confrontation, Jett starts monologuing but it turns out Alicia had actually put him and the entire room into a time loop while she assessed the situation.
In Pact, where declaring that you are going to do something and then following through holds metaphysical weight, the laws of the universe actually encourage gloating to your enemy before you attack them, because it allows you to get a greater benefit out of doing so and gather power to recoup what you lose in the attack. Genre Savvy characters, however, do recognize the value of a bullet.
Satan likes his Evil Gloating in Old Harry's Game. Several episodes have him place a bet with the Professor about how horrible humanity is, with the stakes simply being that if Satan's proved right, he gets to gloat about it.
Infernal. Exalted. They can reduce their Torment meters by doing something their Yozi patrons like. As it happens, She Who Lives In Her Name enjoys an impressive feat of Evil Gloating, meaning that a Green Sun Prince who wants to pursue his own agendas without losing control may well have to rant like a B-movie supervillain.
In Tomb of Horrors, at one point the module suggests that the DM engage in evil gloating if the party falls for one particularly sadistic trap.
Time Lord, the 1990s licensed Doctor Who RPG, gave villains a negative "Gloating" skill. If they captured a player character, they would be forced to roll against it, and if they "succeeded" they would waste time monologuing.
In Pokémon Live!, "It Will All Be Mine" is basically Evil Gloating in the form of a song.
In Wolfenstein, Blazkowicz comes across a Nazi officer standing in front of a Veil portal. His gloating is interrupted when he is rather violently Killed Mid-Sentence by a giant, mutated abomination that telefrags him.
Imbeciles...You would knowingly shackle your heart with a chain of memories born of lies? You would be one who has a heart, yet cast aside your heart's freedom? You turn from the truth because your heart is weak—You will never defeat me!
In Mass Effect, it turns out that even the machine gods aren't immune to evil gloating. Sovereign tells you that there's nothing you can do to stop him and the other Reapers from wiping out all sentient life in the galaxy. It also claims that you're just a tiny insect compared to it and that you have no way of understanding its nature, and yet there it is delivering its evil speech. Subverted at the end of the third game; it turns out he was lying like a rug about his motivations.
In Mass Effect 2, Mordin's loyalty mission features an enemy krogan who will gloat at you on and on if you don't take the Renegade Interrupt option. Which will be available for his entire rant. The gloating goes on so long it's got to be some sort of record.
Kane also gives a good one to Mike McNeil after breaking through the Hammerfest defenses in Tiberian Sun and stealing the sonic crystals, leaving behind a broadcast in which he glibly informs him that the sonic tank "will make an excellent addition to my collection", and that he is sorry to hear that McNeil's brother died a slow and painful death in the raid.
Subverted in Ratchet & Clank 3 where Ratchet throws a wrench at the big bad as soon as he opens his mouth to gloat.
Strictly speaking, he throws his wrench at the remote control for his uber weapon just about to target Veldin. Nefarious just stood in the way.
In Soul Nomad & the World Eaters, ALL the villains do this. Gig also does this from time to time, despite being on your side. The best example of Evil Gloating comes from Levin, aka Raksha the World Eater.
Levin: You don't like that I've learned all these fancy new words? Well tough shit! I'm feeling verbose!
SHODAN does this a lot in the System Shock series. In both games she taunts the player that she is superior to you in every way because as an AI construct, SHODAN has access to more human information and more control over machinery that any human on Earth could ever even conceive. She also explains how being an organic life form makes you inferior and in the second game, she says that the only thing she likes about you are the cybernetic implants she gave you. She especially does this as you traverse the levels trying to find her, but when you show up for your showdowns with SHODAN her taunting amounts to nothing more than mere Boss Banter.
In one of the last stages of Jedi Outcast, Fyyar goes off on a monologue, while Kyle casually finishes the objective he was performing before he was interrupted.
Several World of Warcraft raid bosses do this, especially if you start wiping. Kael'thas and Malygos have raised it to an art form.
And after he succesfully does the above... He proceeds to gloat enough to allow Tirion Fordring to summon Heroic Willpower and ruin all his plans in one strike.
Keal'thas also does this in the Frozen Throne Campaign, where he tells Arthas exactly what his and Illidan's plans are, though in that case he is far less of a villain. It does, though, help cause the plan to fail in a similar manner as other villains. Once Arthas knows the plan, he takes a faster route to the Lich King, and arrives in time to organize the forces and fight back.
Wesker truly is the epitome of this. He's got it so bad, it's to the point where he literally has a gun pointed straight at Chris' head, and had a perfect opportunity to just off him right there. Except... he ends up just gloating and trying to convince Chris exactly how wonderful of a God he will be.
The Darkness "Awwww, what did they do, Jackie? What did they do to Jenny?"
In the third Ace Attorney game, Dahlia Hawthorne lays bare the sheer contempt she feels about the Fey clan and Phoenix; she's dead, having been channeled by a medium, so she believes she's beyond punishmment. Boy, is she wrong.
You can gloat over any captive, a process which earns you a point of notoriety; super agents, however, are the only ones where assigning them to be tortured will automatically cause your Evil Genius to wander over to laugh maniacally at them - a process which can be exploited by moving them a long distance from the torture chamber, causing the super-agent to just sit there waiting for your arrival before the pain actually commences.
NEXUS: "You have five minutes, Commander, and then it's frying time! MUAHAHAHAHAHAHA!"
In Jak 3 Veger taunts Jak right after Damas dies, taking exceptional glee in telling Jak that he was his father and that he died without knowing.
In Metro 2033 you get catured by the Nazis and they decide to just execute you on the spot rather than draging a badly beaten up prisoner with them. While the gun is pointed at your face, there is still enough time for two stranger to sneak up on the Nazis and kill them with knives. Then they come to check on you and one of them lampshades the situation for all it's worth:
One thing I like about the bad guys. There's always a lot of discussions before they get around to pulling the trigger.
Doctor Horrible's Sing-Along Blog has both Captain Hammer's gloating to the Doctor that he is going to sleep with the girl of his dreams, and later on, Horrible's awesomely gloating counter in the form of "Slipping."
Also subverted earlier, as Dr. Horrible tries to get his gloat on but gets sidetracked by his romantic problems:
All right. The wait is over. This, my friends, is my freeze ray, which, with the addition of the Wonderflonium I obtained at my famously successful heist last week... I say successful in that I achieved my objective. It was less successful in that I inadvertently introduced my arch-nemesis to the girl of my dreams, and now he's taking her out on dates, and they're probably going to...French kiss or something. She called him sweet? How is he sweet? [long pause] Right, freeze ray!
Another suspension-of-disbelief moment in lonelygirl15, when Edward Salinas broadcasts a video straight to TAAG's IP address for this purpose.
Pretty much every villain from the web fiction serial Dimension Heroes displays this trait to some degree.
Worm features a lot of villains and hence unsurprisingly this trope is seen in pretty much every one of them that can talk and one or two that can't. Even some of the heroes join in. Though the Extermination Arc established that the most powerful entities for both sides don'tbother with it.
After Elan defeats Lord Kubota and is about to bring him to trial, Kubota proceeds to gloat that he will never be charged, and that he will get off scot-free due to being an apparently Magnificent Bastard. Vaarsuvius disagrees.
Subverted earlier with Elan's Evil Twin Nale: after Elan catches him with Haley in a compromising position, Nale proceeds to gloat at Elan's stupidity at not seeing that Haley is evil and has been selling out the Order of the Stick. The catch is that none of it is true, and Nale is gloating about something that never happened, but since Haley is afflicted with aphasia at the moment, she can't defend herself against the evidence at first.
Nale even lampshades it earlier. He did gloat out all his plan. Only he did it securely alone, to the mirror, in order to get the urge out of his system.
Girl Genius takes a stellar use of this trope when Lucrezia Mongfish, in Agatha's body, turns Klaus Wulfenbach into one of her slaves and gloats about a wonderful Heterodyne-Wulfenbach alliance to come. Klaus even says, "Heard you gloat too many times." However, the self-congratulater is undone by her own pride. Watch it here.
One of the previous Heterodynes was apparently plagued by the habit of gloating prematurely or decided to leave some advice to future generations and inscribed onto the stairs a list of things that must be taken care of before it's safe to gloat.
In thisNodwick strip, a captive explains that he knows the entire plan because the villain has gloated about it. Over and over and over and over and. . . .
Ludwig Von Koopa in A Day With Bowser Jr. He has an evil monologue in every episode in which he's appeared so far, even to the point of being interrupted by Bowser who literally shuts him up in the middle of his monologue. Also Nerdy, to some extent.
For some reason, in the chapter bROKEN, Bun-bun goes curiously Genre Blind and does this to Oasis after trapping her, even though he's not even the villain in that situation. Of course, right then something new is revealed that makes it backfire.
Frans: Did I hear one of you ask how this glory can be real? I remember... when you stormed my mansion, and you alone cut through my army of ninjas... And I kept hearing... "He's just one man! He's just one man!" I didn't realize it until then, but that was how I defeated all of your peoples in the 80's. I was just one man. And now I am just one man again! And I'm killing you! HA HA HA HA HA HA HA HA HA HA!
In Homestuck, Doc Scratch indulges in this after all of his plans have been realized. The very last word he leaves behind before he dies?
S u c k e r s.
Captain SNES, the Eater of Dreams is telling Frog, Palom and Porom that he's going to use his reality warping powers to take the next 10000 turns to torture the twins to a horrible death and make Frog helplessly watch. Unfortunately, because of a Virus spell, EOD doesn't notice his own HP run out.
In Dominic Deegan, The Beast loves doing this. The fact that this has let someone intercede to stop him from killing his enemies something like 4 times in under an hour, you'd think he'd learn by now.
In Kid Radd, near the end, the Big Bad does this to the titular character while he's charging up his Mega Radd, an attack that they both know has near-unlimited power and can easily take out anything in one hit.
Boondocks character Colnel H Stinkmeaner is quite possibly the king of this trope. Every single word he says is evil gloating. At one point he even dies goes to hell and basically gloats that he is more evil than the Satan to which Satan readily admits
Even good guys gone bad suffer from this. In an episode of Beast Wars where Rhinox is turned into a Predacon and nearly takes over, this is what trips him up:
Megatron: Even now, Rhinox, you're teaching me a valuable lesson...
Rhinox: Yeah? What's that?
Megatron: Sometimes Predacons gloat too much! * ZAP*
Kyle Rayner: "Wait! Don't you want to talk first? You know, banter back and forth to show me your innate superiority?" Sinestro: "No."
When Starscream of Transformers Animated wanted to destroy Megatron by using his clones as bomb decoys, he just had to gloat instead of detonating the damn things, giving Megatron and crew time to get clear and let the Autobots save the city. In fact, in this series Starscream is addicted to evil gloating, spending time bragging instead of offing the people he wants to off, like Megatron.
This is averted with Megatron (the only TF canon where it is averted, come to think of it), who stands over Optimus and gloats that he's going to finally destroy the person who left him as a head for fifty years before turning right around and blasting the slag out of Starscream, the guy who actually did it.
This guy takes his evil gloating really seriously. He got pissed off when Bumblebee interrupts him.
In Spider-Man: The Animated Series, Episode "Venom Returns", Cletus Cassidy gloats briefly about how everyone is going to die in 30 seconds due to a bomb he strapped to his belly, only Spidey takes advantage of this by taking the bomb off his stomach by force (and surprise) and throwing it at the sky, saving everyone.
In The Simpsons, Mr. Burns is known for doing this, (Springfield's organized crime community is relatively less prone to it) but an especially sickening example is in Who Shot Mr. Burns part 1. At the town hall meeting about Burns' plan to block out the sun, Bart is telling the people at the meeting about how his dog was crippled by Burns' oil drilling operation; Bart shows the town the dog's cast and everything, and Burns walks in at this exact moment and says "oh, those wheels are squeaking a bit; perhaps I could sell him a little oil!"
Subverted when Homer ends up owner of the power plant:
Homer: Mr. Burns reign of terror is over! And today begins my reign of terr...
Lenny: Man, I thought he was going to say "terror"!
Carl: I didn't think he was going that way.
In one of Sideshow Bob's schemes to kill Bart, he places him restrained on a conveyor belt, which apparently includes the option of "gloating speed" for Bob to give a triumphant verbal bashing long enough for his family to arrive and save him.
In "Imaginationland", he finally has Kyle submit to his agreement to suck his balls, however he insists on making a huge ceremony and gloating endlessly in Kyle's face long enough for it to be interrupted three times over.
Aku from Samurai Jack absolutely loves evil gloating. He's already doing it mere moments after being born.
Aku: Ooohhh... YOU. Thank you!
Samurai Lord: No, my intention was to destroy you!
Aku: Oh? HA HA HA. But it was your poisoned arrow and your hocus pocus that set me free! AH HA HA HA HA HA HA HA.
In the Family Guy/The Simpsons crossover, Peter and Homer start a Giant Chicken-style fight over which beer is better (according to Homer and Moe, Pawtucket ripped off Duff). Both end up falling into a vat of radioactive goo, get radioactive powers, fly into the sky, and continue their fight aboard Kang and Kodos's Flying Saucer. Eventually, Homer loses his powers and grabs on to keep himself from falling to the ground. Still powered, Peter starts telling Homer what he'll do to him... then he too loses his powers, laments talking for too long, and falls.
Now that you have finished reading this article, NOTHING can stop us! MWA HA HA HA HAAAA...