Before the Ordinary High-School Student (or a hidden Bad Guy) can access her (or his) secret powers, there must be a power-up. This usually involves a change of form or at least costume, although the precise mechanisms usually vary by type. In Japanese television, this is called (a) henshin. By genre, this usually goes as follows:
Super Mode: An already-powerful hero or villain becomes even more powerful to face the latest threat. While generally not as elaborate as the previous two transformation sequences, it often signifies a more intense upgrade. The raised power level is usually indicated by a colour change, glowing eyes (or hair) or appearance altered in other ways than a wholly new costume and accessories.
Other Sequences: Ones that aren't covered by or overlap with the above include Mon "evolution" sequences (which are sometimes permanent), characters combining into one, or more mundanely, a superhero donning their outfit via conventional (if accelerated) means.
The Clown from Spawn becoming the terrifying devil Violator. The detailed transformation in the movie is particularly disturbing.
Iron Man occasionally has one, depending on the title and era (for instance, it's very rare to see him activate the suit in an Avengers comic). The most typical one involves assembling the armor from a briefcase. This was abused a bit during the late 90s and early 2000s when every new writer on the Iron Man title introduced their new, super-advanced armor technology, like the SKIN armor, Tin Man and Ablative armor.
In the first issue of Blue Beetle (New 52), Jaime's first transformation into Blue Beetle is shown in nine detailed panels. His later transformations usually take one panel.
In WanderingWordsmith's Thawing Permafrost, Pandora the Shikigami explodes into a weird white goo, then reforms into the commanded form if it can manage it; otherwise, it just flips back to its normal form and collapses, exhausted.
Underworld and Underworld Evolution, with static vampires (except for the main vamp boss with the somewhat typical beastly demon-form) but human-werewolf transformations, and their werewolves have inverted knees digitigrade legs.
Not much outright transformation was shown in the first movie, the most notable sequence being one shot where two lycans change back, as well as one sequence where a character had an aborted change. The second film had some decent shots of man-to-wolf changes, but they went quick because they were mooks.
There are a number of these in Van Helsing, most notably the werewolves who transform by ripping their skin off.
Fright Night had something like this with Evil Ed turning back into a human from being a wolf, and the vampires have 3 stages of transformation.
The 80s remake of The Fly, though that happens by degrees over a long period of time. They're also completely terrifying.
Ghostbusters has the scene where Dana and Louis turn into Terror dogs; it's quite a disturbing process, though.
Also, the sequence where a ghost librarian turns into a hideous ghoul.
And the original has Jerry Lewis going through some grotesque transformations quite out of the tone of the rest of the movie.
Videodrome is just plain weird in general but the transformation parts are even weirder.
Steven Chow's God of Cookery takes this to absurdity with Magical Chef Transformation Scenes. A character (not the lead) takes a power pose, his clothes fly off in all directions and underneath he is already dressed as a chef, all that is required is that he put the trademark hat on.
Gremlins has a very important rule: "Don't feed them after midnight." If you do, the Mogwai goes into a slimy cocoon and mutates into a hideous monster. Unfortunately in the movie somebody makes that mistake as well as getting them wet (causing them to multiply, which looks incredibly painful).
There are several gruesome gremlin-related transformations in Gremlins 2: The New Batch, including those involving a bat, spider, fruit, electricity, and even a woman!
The Witches of Eastwick has the final scene in which the three witches mix up the body parts of a voodoo doll that resembles the main antagonist Daryl (Jack Nicholson) who at first turns into a giant, but then turns into a worm-like thing.
Pretty much every adaptation of the Jekyll & Hyde story, though the transformations are often fairly restrained in the less campy versions.
The 1932 film is not very campy, and its transformation sequence was at the time a major breakthrough in special effects.
The musical does an interesting variation: Jekyll changes into Hyde by... turning his head to the left, hunching a bit, and having the lighting change. However, if the actor is good enough, it works, especially at the end when he's doing a duet with himself and changing back constantly.
In Mary Reilly, John Malkovich undergoes one of the most gruesome and spectacular Jekyll / Hyde transformations ever committed to screen. Then, afterward, he looks exactly the same.
The Mark VII is probably the most egregious: Tony would wear tracers on his wrists, with the armor (in a large capsule shape) summoned via voice-activation to latch onto the tracers and form around his body. It is practically useful on-the-go... or falling downwards after pissing off a megalomaniac Big Bad.
The Mark 42 is relatively low-key. Tony tries to design it for an effective sequence, but it often goes wrong due to being a prototype. On the other hand, the armor can assemble on anyone he points to, such as Pepper or the Big Bad.
Since The Avengers, Tony modified the Mark VII and built his armors from then on so that they can open up for him to simply step in after which they close up around him, making the transformation even more low-key. They can also form around him in midair like the original Mark VII but at a much faster rate. Even Rhodey's Iron Patriot armor has this feature.
Thor, while spending almost an eternity wearing his Asgardian dress armor, loses it after being sent to Earth. After sacrificing himself to the Destroyer,Mjolnir flies to him and strikes him with lightning, forming his traditional armor. His helmet, apparently, is a separate piece and not always worn. Later movies show that Mjolnir also allows Thor to change between different forms of his armor, whether it be by summoning a storm or just magically changing his clothes.
Several of the Star Wars movies will have starfighter pilots immediately precede a space battle with an order to "Lock S-Foils into Attack Position.", a process that usually involves the wings unfolding or splitting apart. Given George Lucas's love of old war movies and airplanes, it was likely a nod to the Dive Brakes that dive bombers would extend before going into a dive, as seen in this footage.
Animorphs: Characters who morphed had to wear tight clothing or risk becoming naked when they remorphed. The latter only occurred once. The books made it quite clear that morphing almost never happened the same way twice, and was usually highly disgusting unless the morpher had an unusual talent for it (as did Cassie).
In the Discworld series, both vampires and werewolves can transform, vampires into either a swarm of bats or one really big bat. Not much detail is given to werewolf transformations, but there is at one point a fight between two of them where they're both in a constant state of flux between forms. Angua, the werewolf on the watch and Captain Carrot's girlfriend, is stated to be perfectly comfortable with him seeing her naked in either form, but doesn't want him to see her mid-change.
Gaspode is surprised when he sees Angua change — expecting the usual horror sequence, he instead describes it more like "A full-body sneeze."
In Winni Allfours, the protagonist is a girl who wants a pony. When that's denied to her, she chooses to turn herself into a pony. Two whole pages of the small book are dedicated to showing her change from little girl to tubby little pony.
Very slowly things began to happen...
The many and varied Ultra Series usually involve a man-to-giant-alien-robot-thing transformation.
Pretty Guardian Sailor Moon (2003-2004) showcased several different transformations managed via digital effects. The results ranged from Moon's clumsy and cringeworthy transform (the first created by the production team) to Dark Mercury's showstopper (the final transform created, after the team had gained months of experience with their tools).
As with its animated counterpart, we see only one or two instances of de-transformation, and these also appear to be simple acts of will.
Additionally, we get to see one transformation — Minako to Venus — from the "outside", as an eyewitness on the scene would. Instead of all the fancy effects, it's an instantaneous, blink-and-you'll-miss-it change that she performs while running, thus validating years of fan speculation.
A later sequence, however, has Ami transforming. Unlike Minako, however, she gets a blue glowy thing.
They also fondly parodied the trope in one of the supplemental shorts: Mamoru becomes "Tuxedo Mask" just by putting on a tuxedo, top hat and mask, but the one time he does it on camera, it gets all the same fancy shots, edits, and sound effects as the girls' magical transformations.
Many, many, many Kamen Rider characters had this... until 1989. Actual sequences were common in the Showa era; even the enemies had transformation sequences, even if they amounted to little more than the camera zooming in on them, blurring a bit, and revealing the monster from its disguise. For the revival era (Kamen Rider Kuuga and onward) they were mostly phased out in favor of transformation special effects done on the fly. (By now, though, they're as elaborate as any full sequence.) Just about the only Heisei series to use honest-to-goodness stock footage Transformation Sequences is Kiva, and only then for form changes (and Dark Kiva.)
In several early Kamen Riders, the pre-change gestures were as epic as the sequences (also not so much nowadays; you may get the Transformation Trinket held in the air during the call of "Henshin.") and enemies sometimes stopped the henshin gestures by attacking during the middle of the gesture, or setting traps that would halt them. The first Rider's pose is very iconic and recognized in Japan, to the point that even the How Do I Shot Web? sequence in DokiDoki! Precure has the new hero yell "Henshin!" and do the Rider-1 pose.
Likewise, episode 2 of Kamen Rider Gaim has Kota trying out several transformation poses in his bedroom, includingAmazon and Super-1's. Interestingly, in Gaim, only the more idealistic Riders like Kota and his little brother-figure Mitzusane/Micchy bother with transformation poses; their more cynical rivals like Kaito and his minions just don the belt, say "Henshin", and change.
The "transformation chivalry" was humorously acknowledged in the first Kamen Rider Den-O movie: the Big Bad's minions attack Ryotaro as he attempts to transform, causing Momotaros to angrily shout "Bastards! You're not allowed to interrupt the transformation sequence!"
Subverted in Kamen Rider Double when the Arms Dopant fires a goo "bullet" that plugs up Shotaro's belt, preventing him from transforming.
The "chivalry" aspect was parodied in the net-exclusive comedy shorts produced for Double. Kirihiko asks Isaka why he didn't attack when Accel transformed into his Super Mode, Trial. Isaka responds that he was "obeying traffic laws"note Trial's Transformation Trinket has a miniature traffic light on it, which changes from red to blue when activated.
The Darker and Edgier Heisei series like Kamen Rider Blade and Kamen Rider Faiz tended to have transformation chivalry less frequently, with characters often walking or even fighting in mid-transformation. Debut appearances always played it straight, though; probably best illustrated in the first episode of Blade, where Kazuma's belt orbits his body several times, trailing a "tail" of cards, before finally settling in place around his waist.
Transformation chivalry is enforced in some series by the Sphere of Power or other transformation effects being absolutely impenetrable, deflecting attacks and painfully repelling villains who attack in midmorph. The aforementioned Blade series was the first to do it: the card-shaped field of energy with his spade symbol on it that passes over him to change him (unless he's pissed. Then he charges straight through it instead of waiting.) is something you do not want to smack into facefirst.
Kamen Rider Decade and its Super Sentai counterpart (see below) Kaizoku Sentai Gokaiger both feature variations on the theme, since both those shows focus on heroes who can use the powers of their precursors. When Decade changes into a past Rider, it's represented by that Rider's usual Transformation Special Effect, except that it's happening to a suited-up Decade rather than an untransformed human as normal. For the Gokaigers, the initial transformation into Gokaigers is a straight Transformation Sequence while their changes into past teams are more simple (usually: team emblem flies out of their Transformation Trinket, lands on their body, and their suit changes in a flash of light), except in the special episodes where they unlock a past team's true power by coming to understand that team; in these cases, they get honest-to-goodness Transformation Sequences based on the originals.
Gokaiger's past Ranger powers are the powers of the actual past sentai heroes, meaning few returning characters get to change and fight, so we don't get to see a lot of old morphs done with modern effects like Decade below does. However, we do get one for the Black Ranger ofChoujin Sentai Jetman, because he is actually still dead. However, when the Gokaigers do the above-mentioned focus episode transformation sequences, we get some idea of what the old sequences would look like if made today.
Also, these series feature old-school characters with modern effects, and in Kamen Rider terms, modern rules, which means we get to see what several transformation sequences look like in "real life." Kamen Rider Black and Kamen Rider Black RX get to change side-by-side with real-space versions of their classic sequences, and it is awesome. (Mind you, in those actual series, when Kotaro would transform with no stock footage sequence it would simply be a flash of green.) Also, in The Movie of Decade, we get to see Shadow Moon's transformation for the first time ever (as in Kamen Rider Black proper, Nobuhiko was in this translucent cocoon-thing until emerging in Shadow Moon form once his powers matured.) Interestingly, Kamen Rider Kiva still has form change sequences when Kiva's doing them (Decade's Kiva changes, like all his changes, are real-space.)
And it is also seen in Saban's adaptation, Masked Rider. It's brand new, as Kamen Rider Black RX's change was nothing but the belt appearing and getting glowy, at which point the transformed Black RX would be seen in real-space (in fact, several old Riders' transformation sequences are elaborate belt-summoning and activations without showing the actual suit formation.) but it looks very much like something you'd see in old-school KR. The form changes are RX stock. Also, Robo Rider gets to transform onscreen (no sequence) where Shadow Moon didn't.
Another adaptation, Kamen Rider Dragon Knight, gets a much fancier transformation than the Kamen Rider Ryuki original did, complete with the monster-repelling Sphere of Power seen in more recent Japanese KR series. No stock footage sequence, though - it's all real-space, like modern KR. However, one small part is stock footage: the closeup of the Advent Deck being inserted and spinning is the same every time. Of course, that didn't save 'em much time and money, as there were thirteen Ridersnote More if we count all the Ventaran Riders. However, this doesn't affect the Advent Deck spin. and one Advent Master, and we only saw some characters change once.
Power Rangers: In the earlier seasons, the usage of Stock Footage became quickly grating, as the rangers would look the same at the beginning of the sequence, regardless of what clothes they'd been wearing beforehand or changes in their hairstyle. In later seasons, it became standard to use clever tricks to downplay this; many seasons have the Rangers wearing uniforms or otherwise having a Limited Wardrobe before the (full) sequence begins. In several other seasons, the sequence is cut such that their pre-transformation clothing is hidden during the sequence using close-ups and visual effects.
Occasionally, a shorter Stock Footage-free Transformation Sequence was used instead, which, with a very few exceptions, used a much blander and more generic special effect. As seen in "Countdown to Destruction" as well as several other times throughout the various series, the actual transformation is in fact instantaneous and consists of nothing more than a small explosion or just some glowing masking the shift — the drawn-out sequence is purely for the audience's amusement. We see this in action for the first time in Power Rangers Zeo, where three Rangers dramatically run up and change in-scene. By now you're used to it, several in-scene changes in an episode and the "real morph" saved for the big final battle with the monster, but back then, this was after four years, at a time when it just wasn't done, and there was a lot of HSQ in it.
The Mighty Morphin' Power Rangers transformation sequences weren't very elaborate... so in "Once a Ranger" a new, snazzier sequence was made for Adam (the second MMPR Black Ranger) so he wouldn't be the only one without.
Adam's old morph was Screwed by the Lawyers. At the time, Disney had rights issues with MMPR, so they were forced to scrap the old sequence entirely (with an unfortunately generic song played along with it, as they couldn't get the MMPR music either).
The record for most sequences in one season - MMPR season three. We've got civilian to ninja suit, civilian to Ranger (all new ones!), ninja suit to Ranger, Rangers to Metallic Armor mode, and then the five Alien Rangers.
Then there's Justin's transformations in Power Rangers Turbo, which have a little bit added compared to the others to show him growing to adult size.
Like everything else in Power Rangers, nothing is safe from lampshading by RPM. Not even morph sequences.
Ziggy: Sometimes when I morph, I can't help but notice this gigantic explosion right behind me for no apparent reason.
Taken to its logical extreme by Flynn in the same episode, where he clears up a plot-induced fault in his morpher (energy buildup) and simultaneously ramps "one of Ziggy's runoff explosions" Up to Eleven, catching Tenaya and a whole squad of mooks in the blast!
Surprisingly subverted in Mighty Morphin' Power Rangers. In the time it takes for the rangers to suit up, the bad guys flee the scene to set up an ambush.
Beetleborgs has the drawn characters leap from the comic book which opens up, then the kids, drawn up as a comic book page, standing side by side. The armor appears slowly, then the three Beetleborgs step forth, with the Koosh Explosions turning into real flashes of yellow light as the Borgs go from comic-booky to real life Metal Heroes. Later in the series, the pictures of the kids morph their chosen suits.
VR Troopers gets them, with the VRT actors' faces beneath what's mostly the Metal Heroes' original Japanese transformations. Holding up the Virtualizer pendants is new.
Speaking of the Metal Heroes franchise, the Space Sheriff Trilogy makes it perfectly clear that the Transformation Sequence is for our benefit. After an instant "flash of light, morphed now!" change, we'd get "[Hero name] takes 0.0[small number] seconds to equip his suit. Let's take another look at the [morph command] process." and then the changing sequence, which is a flashback.
The Makai Knights of the GARO franchise are quite minimalistic in their sequences, which usually involves them swishing their weapons (swords/staffs/spears/bows and many others) into creating a hole in reality through which their Makai Knight armors would assemble in their body at split-second rates. Quite justifiable in that the enemy Horrors of the Makai Knights have no concept of chivalry at all.
Superhuman Samurai Sybersquad gets a hybrid of the real-space scenes and the stock footage sequences. Sam striking the 'power chord' on his guitar is half new footage (constant angle-changing for drama. The alternate angle is stock footage.) as is his transforming into energy and flying into the computer. The energy entering the Servo form on the screen and Servo flying into action is stock footage, as well as Servo's 'decompressing' into his proper size. (The original series is a Spiritual Successor of the Ultra Series, so decompression replaces the heroic Make My Monster Grow to building size.)
An earlier Filmation production of Shazam! from the 1970s had the magic-word-and-lightning transformation between Billy Batson and Captain Marvel. It was usually paired with a similar show, Isis, which had its own transformation sequence.
In a case of typical Filmation cheapness, the detransform from Captain Marvel back to Billy was handled by simply running the transform footage backwards, even though that meant the sequence ended with a lightning bolt unstriking Billy.
In the 1970s The Incredible Hulk series, David Banner (Bill Bixby)'s transformations into The Hulk (Lou Ferrigno) would usually be made specifically for each episode, but there were a few stock sequences that were sometimes used, involving multiple close-ups of Bill wearing colored contacts, his skin turning green, the shirt tearing on his back, and/or a full shot of the Hulk whipping off the remnants of the shirt. In later episodes, it would often happen almost entirely off-screen after the initial shot of Bill's glowing eyes, only the distinctive sound effect indicating anything was happening.
The 1970s Wonder Woman series iconically featured the character spinning in place as she changed from Diana Prince to Wonder Woman. The original version of this sequence showed her spinning and rapidly changing into Wonder Woman (still holding her old clothes and needing to dispose of them). Later in the season, as this effect was more expensive to shoot, this was replaced by Diana spinning in place as an optical effect played over her, changing her into Wonder Woman instantly (and not requiring her to deal with her civilian clothes). Here's six solid minutes of every single transformation from the first season.
The Twilight Zone pulled off an impressive transformation scene despite limited special effects in The Howling Man. A man walks down a pillar-lined hallway as the camera follows alongside him. As he passes behind each pillar, he gets more and more demonic (ending with a cliche horns and tail). It's cut so that it appears to be one long take, but there's no effects on screen at any point.
Manimal, starring Simon MacCorkindale. Though he could transform into any animal, there were transformation sequences only for three animals. And they never explained why he always returned to human form fully clothed despite the transformation sequence's clear depiction of his clothes ripping.
"POWER ON!" By pressing the team's distinctive phoenix insignia, Captain Power and his cohorts would activate the Power Suits which would transform from "patterned longjohns" worn under their uniforms, into actual plate armor with weaponry and personalized devices. Heavy damage to the Power Suit would make them fade back into their inactive shape.
Kitchen Nightmares — in the UK show at least — has Gordon Ramsay "transform" from normal everyman into Super-Badass-Chef-Ready-to-Save-the-Fucking-Day by stripping out of his civilian clothes into a brand-spanking new chef's coat. Estrogen rises predictably.
KITT in the last season of Knight Rider and KI3T in the 2008 TV movie and show.
"Weird Al" Yankovic undergoes a transformation sequence at the start of his video "Fat" that fortunately does not strip him nude in the process.
Similarly enough, the music video for "Right Here, Right Now" has a transformation sequence based on the theory of evolution.
In World of Warcraft, the Worgen race can switch between a human form and a werewolf form. When becoming a werewolf out of combat they exhibit a rather elaborately animated transformation scene; but since they have to be in werewolf form to participate in combat, entering werewolf form in combat is basically instantaneous.
Then again Disgaea 3 and the PSP remake of Disgaea 2 plays this straight with the "magichange" feature (which allows a monster type unit to "merge" with a humanoid unit by acting as a weapon for them), although only the monster unit transforms.
The Breath of Fire series is the king of this trope for video games, since the main character of each game (all named Ryu) can transform into a dragon, with a more elaborate sequence in each game. Furthermore, in the first and third games, a second character has a transformation sequence (Karn in Breath of Fire I, and his Fusions; Rei in Breath of Fire III, and his Weretiger transformation), and the fourth game's antagonist, Fou-Lu, is playable and can also transform into a dragon in a sequence largely identical to Ryuu's.
The Legend of Dragoon has individual anime-like transformations for every single playable character in the game, as they turn into their Dragoon forms. One villain also gets a mid-battle transformation into a Dragoon with his own sequence. Dart, the main character, gets a second Dragoon form late in the game with an even more over-the-top sequence.
Luckily there was a menu option to replace the sequence with a much shorter "Normal form Flash Dragoon form" sequence.
But you still got the full transformation sequence of the character who initiated the "transform all" Special command.
Saiyuki: The Journey West features characters who can transform into monsters. Each one has an elaborate transformation sequence and an equally elaborate reversion sequence. Furthermore, there's two more sequences for transformation and reversion used in cutscenes (even though they otherwise use the same sprites!)
More minor transformation sequences are used in Final Fantasy VII (Vincent's Limit Break) and Wild ARMs 2 (Ashley's transformation into Knight Blazer). These pretty much are of the "original character fades out, new form fades in" variety rather than the flashy sequences mentioned above, though.
This trope is arguably the entire point of Final Fantasy X-2. Luckily, there's an option to shorten or turn off the transformation sequences after the first time the girls have changed into their new Dresspheres.
The character of MOMO in XenoSaga gets powerups that can be used once per fight that include transformation sequences.
Every single villain and hero also transform in the Star Force games, though admittedly usually everyone except for Geo gets theirs shortened to a quick fade to white and back.
The Tekken series has quite a few. Including Devil Jin's ending from the fifth game and Ogre's transformation into True Ogre in Tekken 3.
Transformation sequences were an oft-requested feature in City of Heroes, and a small set of four costume-change emotes are now available as part of the Magic Booster Pack (released in Spring 2009). Another half-dozen or so became available with Issue 15, and each of the origin-themed expansion packs adds one or two as well. They run the gamut from reminding you of Wonder Woman ("Spin") to Captain Marvel ("Lightning") to being reminiscent of the arrival of time travelers in the various Terminator movies ("Energy Morph").
Kheldians and Nictus, the game's resident body-stealing shape-shifting aliens, follow this trope to a T. Switching into their forms involves a moment of concentration and a big, screen-shaking flash of Kheldian/Nictus energy, whereas switching back just makes the human silently pop into existence where the alien used to be.
Super Smash Bros.. Melee has a relatively quick transformation sequence between Zelda and Sheik. This is lengthened in Brawl because of loading, and Pokémon Trainer goes through a similar "transformation" when switching Pokémon, but the character transforming cannot be damaged or intercepted from the time the sequence starts to when it ends. There is still a lag period at the end, though.
Altered Beast has a momentary pause before buffing up when one of the magical floating balls is collected, followed after a third time by a transformation sequence to make you into a werewolf, dragon, or giant cuddly bear with halitosis. The werewolf one◊ is particularly detailed.
The Japan- and Europe-only PS2 game Project Altered Beast has horrifying transformations. The player takes the role of a "Genome Cyborg" investigating a town that has been overrun with "Genome Mist" transforming all its inhabitants into horrifying monstrosities. The main character appears as a human but has the ability to take various forms. No matter which form is chosen, it is accompanied by a gruesome CGI video detailing every aspect of the transformation as limbs blow up and regrow and various organs are mutilated and reshaped, with no limit on the amount of gore.
Diablo 2: In the cutscene before Act IV narrated by Marius, he has the misfortune to witness The Wanderer's horrific transformation into Diablo. Spikes burst out from his back, his face distorts horribly, and it ends with Diablo casting aside what's left of his human shell like a dirty rag.
Pokémon evolution features the creature fading into its outline, and then the outline shifting into the new evolution, before fading back in. You can glitch this process in the first game, resulting in a near-endless stream of (impossible) evolutions.
Gitaroo Man's can be seen here about a minute into the video. His transformation is sort of rushed in further levels, though.
In Mass Effect 2, when Harbinger engages his Villain Override and takes control of a Collector, the Collector's body goes through one of these. Note that he is not invulnerable during the transformation sequence, allowing a quick-witted player to whittle down his shields and armor before he starts attacking. The transformation sequence elevating him above most structures serving as cover certainly helps getting a few good shots in.
You can also do the long version of the sequence at any time by holding the D-pad for the quick-change instead of just pressing it. This lets you see the sequence for powers you acquire as upgrades like muscle mass, whipfist, and the vision powers.
Command & Conquer: Red Alert 3 has the Empire's Tengu launching into a backflip and transforming mid-air when switching between mecha and jet forms. In-game.
To a smaller extent, the Striker VX does it as well. The intro even shows it extending two spindly legs just prior to landing then folding back it's propeller before firing off-screen.
Or for that matter, every single amphibious unit in the game does a Transformation Sequence when going from land to water or the opposite; from Allied Prospectors expanding an air cushion to Soviet Stingrays extending six legs and climbing ashore, Spider Tank style.
Carbuncle from Puyo Puyo, in this commercial, does the usual intro... right before Carbuncle transforms into a handheld with Carbuncle himself inside it.
In the Digital Devil Saga games the characters all transform into demons to fight. The player characters and major NPCs emit glowing Tron Lines from the sigils tattooed on their bodies which extend across them before morphing into their monstrous forms, while minor enemies just summon a cylindrical energy field to surround them before being replaced by their monster shape. The sequence is not often seen though, as players almost always start battles already transformed and only start in human form when ambushed. Although they do have the option of switching back and forth between human and devil form in battle, this is rarely a good idea as human form is, unsurprisingly, much weaker. In the second game the player characters also gain access to a 'berserk form' which randomly happens when solar noise is at maximum, forcing them into a half-transformed state with massive attack power and critical chance, but low accuracy, all spells and skills apart from hunt skills sealed and 0 defence.
When a CPU or CPU Candidate in Neptunia activates Hard Drive Divinity, the user switches into a Stripperific bodysuit, her hair grows (or changes to drill hair in Uni's case), her eyes glow and sport power switch shaped pupils, and her weapon will increase in size or at least change how it looks to fit the appearance of the user; in Neptune's case, her voice is also changed. The Transformation Sequence is very Sailor Moon-esque in the first game and rather lengthy at that, but can fortunately be skipped with the press of a button. Arfoire likewise gets a transformation in the first game as well; into a colossal and powerful dragon, that is.
In Guitar Hero Warriors of Rock's Quest mode, every character gets one when you play their encore song for the first time and they transform into their warrior form.
Angelic Buster has one in MapleStory in the beginning of her class showing her transformation from Tear to Angelic Buster. You can play it as many times as you want.
In Arcana Magi Zero, when Alysia Perez calls for Saga and Megumi Miyazaki calls for Fable, their magic circles would go through their bodies forming their magical outfits and armor.
Yuki Shimizu in The Impossible Man has a Transformation Sequence off scene. The plausible reason was to hide her identity from everyone, even her co-workers. Unfortunately her co-workers already figured out her secret identity and she know its too, but she still goes off scene in their presence when there are no vilains around to transform.
Tom Fury attempts to replioate Ultraman's transformation into his signature gear...but he hasn't quite gotten the hang of it yet.
Kid Sideburns becomes the superhero Captain Mental to defeat Coyle Commander byputting on a mask and having his clothes magically change,
Prior to the climax of Return of the Cartoon Man, Roy undergoes a transformation back into a Cartoon Man so that he can stop Simon's diabolical scheme.
Bee and Puppycat has a downplayed version. Bee's transformation is less exaggerated than most, and Bee groans in complaint the entire time.
Manatee Girl The Movie features one that is roughly a minute long (of a 4 minute 30 second film) and has manatees in space floating in the background. The length is Lampshaded when the mid transformation sequence the main villain checks his watch.
Winx Club and its Spin-OffPop Pixie. The Winx fairies each have completely unique transformations for each fairy form. As of season 5 they have had basic fairy, Charmix, Enchantix, Believix, Sophix, Lovix, Harmonix, and Sirenix, though Sophix and Lovix were one-time transformations. With six girls, this makes 48 different transformations. Add in the movie versions of Enchantix and Believix, and the number is brought up to 60.
Centurions — About a 15-second sequence, as all the various parts of the chosen weapons system would beam in and attach to the hero's exo-frame, ending with the helmet rudely clamping on to the head. Often showed all three heroes transforming back-to-back, and had the same trigger phrase: "Power Xtreme!" (Later episodes of the show usually skipped the stock footage, and just showed the pieces appearing and attaching all at once. The two Sixth Rangers added later never even got the stock footage versions).
She-Ra: Princess of Power: He-Man's twin sister She-Ra had a similar sequence, but it was actually longer (and more sparkly). Like Cringer becoming Battle-Cat, She-Ra's talking horse Spirit would become the winged unicorn Swiftwind.
Spoofed in an episode of Invader Zim. Gir begins a Transformation Sequence, complete with music, lights, and midair spinning... and then simply steps into his dog costume and zips it up.
Curiously, the original appearance of the Transformers in the West did not include overt transformation sequences. The characters would make the switch between robot and vehicle/device forms wherever they were standing in complete continuity with the scene (although they always transformed the exact same way). This is more cultural than cost; newer series such as the shows of the Unicron Trilogy, which were actual anime, frequently featured such scenes, and the Japanese Alternate Continuity third season of Generation 1 featured transformation sequences for new characters only (old ones kept scene continuity). Transformers Animated is generally in-scene but faster than G1, unless the bot in question is about to do something important (e. g., Megatron transforming for the first time after being rebuilt and telling the Decepticons to "Transform and Rise Up").
Transformers Animated also had the Autobots using Japan-esque transformation sequences in the final episode, mostly for dramatic effect.
The were more or less free actions considering that many of them had forms that had the same parts for legs or otherwise the ability to fly (in the above Case, Cheator shifts while leaping in mid air, so never actually slows down, and was still able to pull it off without the transformation itself being any faster than usual). Rattrap shows this shortly after acquiring his transmetal form and used the momentum from his motorized wheels to transition into a flying leap so that he could aim a few gunshots at Megatron without stopping.
Transformers Prime has only one prolongued transformation sequence, which ironically is given to Nemesis Prime, the only non-Cybertronian transforming robot in the show. This is presumably to emphasise his imperfect mechanical nature, whereas actual Cybertronians have far faster and more fluid transformations.
Rescue Bots is probably the first western Transformers series to use transformation sequences on a regular basis.
Ben 10 has ten unique, albeit recycled, sequences. There's one for each alien creature Ben has the ability to change into (though Grey Matter's didn't actually get used until season two). Two more are added in season two, but one was lost after the events of "Ghostfreaked Out". Some are longer and more detailed than others, but all follow the same pattern of showing the change progressing outward from his wrist. Sometimes a simple green flash of light is substituted for the transformation, and red light is always used for Ben changing back. Seasons three and four added more new aliens, but no new sequences, oddly enough. Future-Ben supposedly had ten thousand alien forms but we (obviously) didn't see all of them.
And one-shot villain Doctor Viktor gets his own Transformation Sequence, going from oversized scientist into Frankenstein-ish monster. It's only used once, though.
One particularly humorous moment has Ben's parents (who have forbidden him from using the Omnitrix) managing to catch him in the act during one of his (around 10-second) sequences, in episode 20 of Alien Force.
The old Spider-Woman cartoon series features a transformation sequence for Jessica Drew to change into the title heroine.
The DVD Commentary actually mentions that is a vulnerable opening and part of mastering the Avatar State is not doing that.
It should be noted that Aang did try and protect himself, as he made himself a little cocoon out of crystals to cover himself. Wait a minute, that means this could of all been avoided if it weren't for Power Floats!
He learned from that event, though, and by the time the Avatar state kicks in again, it's instantaneous.
An Animated Adaptation of Shazam! featured Billy, Mary, and Freddy, and a drawn-out transformation sequence. Unlike most, they had sequences for transforming back to normal as well, and a variety of different stock sequences for various combinations of the main characters, transforming singly, in pairs, or all three at once. (Interestingly, the comic version is specifically stated to be instantaneous. In the 1970s it was furthermore stated that, between the speed of transformation and the blinding flash, most people don't know that Billy is Captain Marvel, even when he transforms right in front of them, though that hasn't carried over to post-crisis versions of the character)
In fact, Filmation in general. In addition to the ones mentioned above (He-Man, She-Ra, Shazam), there was also Web Woman, Super Strech and Microwoman, Fantastic Voyage, Filmations Ghostbusters (the 1986 cartoon), and Bravestarr (30-30 had transformation sequences when he went from bipedal to quadrupedal and back), just to name a few.
The series was mostly humorous in intention, and it even spoofed itself. At least one episode had the hero retreat to a nearby doorway to transform, only to be interrupted by an old woman exiting the door. She stopped long enough to give him a lecture.
Like Filmation, Hanna-Barbera was also good at filling time with these sequences. In addition to the Thing, there was also the Mighty Mightor (with a sequence very similar to He-Man, but predating it by twenty years), the Arabian Knights, the Impossibles, the Super Globetrotters, the Super Friends (in the Wonder Twins' segments), Wonder Wheels, Mighty Man and Yukk, the Drak Pack, and even the SWAT Kats.
Hanna-Barbera also spoofed this trope with one version of Captain Caveman. On The Flintstones Comedy Show, he worked as a copy boy named Chester at a stone-age newspaper, disguising himself with a pair of glasses and his cape folded into a bowtie. Despite the minimal disguise, he still required a coat rack and an elaborate transformation sequence (which included heroic music, explosions, lightning bolts, rockets, fireworks, and stars, and was loud enough so that the entire city of Bedrock could hear it) to become Captain Caveman.
Freakazoid!! Had quite a variety of them in different episodes. One had him meeting a werewolf, who used the classic Universal sequence of a still of the human actor, a series of transitional paintings, and finally the actor in full makeup. Freakazoid then says "I can do that too!" and sits in the same chair, transitioning through a series of paintings of him doing weird faces, plus a few random cameos from other characters, before arriving at himself.
Subvert a bit, with Jerrica "Jem" Benton of Jem and the Holograms, which is only a "Showtime, Synergy" to summon Jem hologram and a "Show's Over, Synergy" to remove the Jem hologram — the answer is usually a pink light and very quick.
The Powerpuff Girls: In the episode "Super Zeroes," the girls each try to change their look to be more like the super hero in their favorite comic books, complete with such elaborate transformations that, by the time they're done, the monster has left town.
In the short lived and mostly forgotten 1999 animated series Spider-Man Unlimited (nothing to do with the comic with the same name) he finally got one via nanotech.
The 90's cartoon King Arthur & the Knights of Justice had a transformation sequence for each of the knights as they put on their battle armor. Sometimes it was further padded by transforming their horses.
Once the Skysurfer Strike Force activated their transforming watches, they would transform into heroes and their cars would become rocket boards.
Subverted somewhat in Danny Phantom, as the transformation sequence there is refreshingly simple and short, while still being rather stylish with a chance to play around with it and not use Stock Footage. Whenever the titular character wants to transform into the titular alter-ego he simply focuses for a few seconds, a ring of blue white light appears, bisects and travels over him, leaving one superhero in place. Easy, done.
Most of the time after the first few episodes this happened in Static Shock, even though his costume was just regular clothes altered by the hero to obscure his identity.
Though it was used less and less as the show went on, it was sometimes used to great effect if it happens when Static finally finds a power source to charge his electricity after running low for a while, signifying how powerful he is at full charge.
The Nickelodeon TV movie Groove Squad, which was about three cheerleaders who could transform into, you guessed it, superpowered cheerleaders by drinking a magical red juice. After they drank said juice, the girls went through a rather overdone transfomation sequence to change into their superheroine forms.
Mon-Star, main villain of SilverHawks, has a very similar transformation sequence to Mumm-Ra. One interesting note is that he grows metal spikes from various parts of his body, which is animated in a way that looks fairly painful, but no mention of pain is made.
This was one of the reasons that the Avengers cartoon was so poorly received by fans of the comic. Ant-Man, Wasp, Falcon, and Hawkeye all got elaborate Transformation Sequences that involved being covered by armor that was, for the purposes of their abilities, completely unnecessary. It didn't help that it added to the fact that none of these characters were wearing anything remotely like their comic book costumes.
Parodied in the South Park episode "Good Times With Weapons," in which the kids buy some real ninja-weapons that — in their imaginations — transform them into crime-fighting ninjas through a lightning-transformation sequence... and who end up almost putting Butters's eye out with a ninja-star, as a parody of the potential harm caused by violent cartoons.
Done again in "Coon vs. Coon & Friends", when Bradley plays a superhero called Mint-Berry Crunch who has superpowers he could call upon by turning in place and saying the magic word, "Shablagoo!"
There's also "Korn's Groovy Pirate Ghost Mystery", in which the band is faced with a lynch mob of townspeople and titlar pirate ghosts. Although they're generally a parody of archtypical protagonists in Scooby-Doo-type mystery shows in this episode, Korn launches into an obtuse transformation sequence that turns them into... various types of corn. Even the pirate ghosts are stunned.
Played almost completely straight in the Tiny Toon Adventures short "The Amazing Three", when Babs breaks out the "Acme Little Wonder Makeup Kit" — complete with a outer space-themed Love Bubbles background and Orbital Shot
Lampshaded and spoofed in Megas XLR: when a group of Magical Girls confront Jamie, they transform. Jamie just stands there waiting patiently and bored, until they finally finish after more than a minute.
in The Little Mermaid, Ariel's transformation when turning from mermaid to human. + 1 as she's mostly naked afterward.
There's another transformation sequence in the same movie, though without the nudity. All the in-between stages of Ursula's transformation into Vanessa are extremely creepy, and her Evil Laugh doesn't help.
In the Voltron Force episode "Flash Form a Go", the force meets an enemy that refuses to follow transformation chivalry, ramming the lions apart whenever they try to form Voltron, an act that takes precisely 36 seconds, according to Daniel.
Super Duper Sumos: The sumos goes through a transformation sequence to become "Sumo-Sized."
In Teen Titans, Cyborg had a rather epic one in The End: Part 1. He connects himself to the main Titans Tower power system, unloads some very big guns against a glowing white background with crackling electricity and shoots Slade and his minions with the mother of all sonic blasts. ...Doesn't stop Slade, but it was worth a shot. Unfortunately, this is never used again.
In Teen Titans Go! he does connect himself to the power system again, though this time it's much darker, as not only does he go corrupt with power turning into a Hal 9000 expy. Being "one with the computer" he denounces any humanity he originally had and at the end he knocks out the other Titans and turns into sentient household objects, so they can appreciate the "beauty of being 100% technology" And the episode just ends there. note though since Teen Titans Go!! went for a "Saturday Morning Cartoon" feel as opposed to the drama and seriousness of the original show. All episodes are stand alone, and are meant to be silly. Which turned off a bunch of the fans of the original
One episode of U.S. Acres did this during a Snow White parody. First, Wade's inner tube disappears, causing him to put his hands on his crotch. Then, the bottom of the dress appears, followed by the top of the dress. After this, a wig is put on, and then one hand gets a broom and the other gets a bucket. While this happens, a sappy tune plays.
Sym-Bionic Titan has this in which the three mechas (Manus, Corus and Octus) form into the titular robot.
In an episode of the original Teenage Mutant Ninja Turtles cartoon April O'Neil is turned into a wasp and you see the wings and antenna emerge from her.
She also became a Cat Girl in "The Catwoman of Channel Six", though the only on-screen part of the "sequence" was right at the end. Most of it was a Slow Transformation instead.
Wreck-It Ralph: Vanellope Von Schweetz transforms into a princess after crossing the finish line of her game Sugar Rush at the film's climax. It confused her until she found out she was Sugar Rush's true ruler before King Candy/Turbo sabotaged the game and made her an outcast.