Okay, I'll be honest, for once, I don't have a good feeling with this YKTTW, which is why I'm not going to list just a whole lot of examples, but rather, see if any body else has any thing to add, or, if perhaps, there may actually be a similar trope that already exists (and so far, not to my knowledge).
An extreme character makeover is what happens when a character, or characters, suddenly have a drastic, and unexpected change in their design. These tend to usually happen inbetween seasons of a show, or inbetween installments of an episodic saga, and are usually the results of the creator, or character designer, being displeased with a character's looks; a result of Executive Meddling; the creator simply wanting to experiment; and in some cases, for seemingly no reason whatsoever. Also some rare live examples as well.
Related to, but not to be confused with Art Evolution and Art Shift.
Mattie Franklin as Spider-Woman. She radically altered costume style from issue to issue to the point that it became a gimmick.
Darius Dax, the Lex Luthor Expy in the Supreme comics. In one story line Dax enters a sort of Hypertime afterlife and encounters the different incarnations of himself, including a early prototype who little resembles later versions.
There were some very noticeable changes in some characters' appearances between Babylon 5's pilot movie "The Gathering" and the rest of the series that followed. Given the pilot came a year before the series proper, this was mainly creative tweaking (as some Word Of God has borne out).
Most noticeable in Delenn's and other Minbari's appearance. All of them, including Delenn, had a much more androgynous appearance, and Delenn's voice was also deeper.
Also noticable in G'Kar's. More angular features in the pilot.
Delenn's transformation between Seasons 1 and 2 was part of the in-universe story, a deliberate act of her character to become more like a human in an effort to bridge divisiveness between the two races.
During the first season of The Banana Splits, Snorky was was covered in long, shaggy fur from head to toe, as he was originally conceived as something of a wooly mammoth; for the second season, however, he became a clean-shaven elephant, and had visible eyes. In an internet revival by Cartoon Network in 2000, the original shaggy version of Snorky was brought back, and later still, in a similar 2008 revival, the clean-shaven Snorky was brought back. In some cases, as far as merchandising goes, it is actually not uncommon to see both versions of Snorky.
Noticeably almost all the cast of Degrassi have this at some point. Comparing them when they first appeared to their graduating self always shows the difference.
Almost averted with The Great Space Coaster: a prototype puppet of Gary Gnu was built, originally for the first season, to give the character a more Walter Cronkite-esque demeanor; the prototype Gary had black hair and a mustache, a much smaller mouth (resulting in limited expressions), and more somber colored attire. After it was built, the producers were not satisfied, so Gary underwent a few changes, resulting him looking more like the character he is today (though his mouth wouldn't be built bigger until the second season).
Hogan's Heroes: In the pilot episode of the series, both Newkirk and Kinchloe's respective uniforms were considerably different from what they wore for the remainder of the series; in particular, Newkirk wore a buttoned wool shirt under his fatigues rather than his usual turtleneck sweater, and Kinch wore a khaki baseball cap rather than his wool jeep cap.
When appearing on H.R. Pufnstuf, Stuid Bat was a light grayish blue color, his ears stood up, his wings were basically gray and fushia-colored streamers hanging from the sleeves of the puppeteer's suit, and had a slimmer body. Later when appearing on The Krofft Superstar Hour, he became purple, his ears dropped, his wings looked more like actual bat wings, had a pear-shaped body, and now had freckles on his face.
This happens to Kaptain Kool and the Kongs from The Krofft Supershow as well: during the first season, the Kongs were a lot more glam, wearing wild and eye-catchingly brightly colored costumes, with sequins and glitter not only on their costumes, but on their faces and in their hair (Nashville's hair was even a bright blue color); for the second season, however, the glam aspect of the Kongs' attire was dropped completely, and they then began wearing much more sober, yet still somewhat psychedelic-inspired suits.
M*A*S*H: Margaret went through numerous changes in her appearance over the course of eleven seasons... and the fact that Loretta Swit was occasionally having work done throughout those years didn't help matters either. If you compare her from the pilot, to her in the Grand Finale, she looks like a completely different person.
In the original test pilot episode of The Munsters, Lily was an entirely different character than she was from the series' proper; in the test pilot, Lily was more of an Expy of Morticia Addams (and was also played by a different actress than Yvonne De Carlo).
Kramer was almost a completely different character in the pilot episode. In the pilot, Kramer is known as "Kessler", has short curly hair, really heavy stubble, and perpetually lounges around in his bathrobe and underwear.
The character of Tim Whatley changes his looks with appearance on the show: first he had shaggy hair and a beard, then he shaved the beard off, then he cut his hair short and grew the beard again, then lost the beard again while keeping the short hair.
Notably Oscar the Grouch, who started off during the first season with bright, neon orange fur; at the start of the second season, and onward, his fur was a dirty green. In-universe explanation was he went on vacation at a resort called Swamp Mushy Muddy, where the atmosphere was so damp, it turned his fur green overnight; real-life explanation is that Jim Henson suddenly decided he wanted the character green instead.
Big Bird went through a makeover as well: he originally had very little feathers above his eyes, and pointy tallons (much like real birds), but towards the end of the first season, he had much more feathers above his eyes, thus giving him an actual head, as well as rounder toes.
Also, in the first season, a greenish monster with a reddish nose, and a red lip inhabited the street, and was known as Mr. Fuzzyface; starting in the second season, this monster's fur was changed to blue, his nose was changed to pink, and he became Grover.
World's Dumbest...: Michael Loftus has a tendancy to change his looks on a frequent basis; this can be really confusing when watching randomized episodes in reruns, and see him with short hair and a clean-shaven face one episode, then see him with fuller hair, a goatee, and glasses the next.
Bloom County had major Art Evolution over the course of the years it ran, but did have one major change to Steve Dallas when he was abducted by aliens who trans-reversed his brain. He lost the perpetual Cool Shades, gave himself a perm, and stopped dressing like a slobby 80s frat guy.
Most notable was Flemeth, who was a scraggly old woman in the first game but became something you'd find in Hollywood in the second. Wrinkles vanished, her hair became much more coiffed, and her body may as well have belonged to a 20-year-old.
Entire races underwent changes. Elves' bodies were elongated - their necks and ears especially - and the qunari grew horns.
For the first four seasons of Arthur, D.W.'s friend Emily had short hair, and wore a pink dress with red flowers on it; Emily was then Put on a Bus until Season Seven, where she returned with much longer hair, and now sporting a blue dress with green flowers - a look that has stuck to this day.
For a brief period of time in the early 1940s, Elmer Fudd went through a drastic makeover, turning him into an incredibly rotund character, turning him into a caricature of his voice actor, Arthur Q. Bryan; fans reacted negatively to this new version of Elmer, and shortly afterwards, was returned to the Elmer most people know and love him as.
The early Looney Tunes character Egghead was the prototype Elmer; in fact, some of Elmer's early official appearances, he dressed in Egghead's brown derby and green suit.
The Recess gang in the original test pilot short look nothing like the ones who know and love today. Mikey is the only one who looks the same in bother versions, but the other characters have either subtle, or obvious differences, including Gretchen (who has really dark hair, bigger buck teeth, and wears a polka-dot dress), Spinelli (who is a lot smaller, has really messy hair sans her signature tobaggan cap, and wears a messy and tattered dress), T.J. (who has spikey red hair sans his trademark backwards red ball cap, is considerably leaner, has a bigger nose, and wears a bowling shirt with one red suspender over his shoulder), and most notably Vince (who has a much rounder head with really short hair, bigger eyes, and wears a red jersey).
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.