Atomic Robo loses his shirt in nearly every action scene, yet his pants have survived train crashes, an exploding steam-powered pyramid tank (Don't ask), and being blasted from orbit by a militarized satellite.
Done pretty well in the third Blue Beetle's (Jaime Reyes) run; the magical/alien scarab implanted inside his body generates his armour at will; it also apparently uses whatever spare molecules are lying around to make his clothes when he needs to. For the first couple of issues, he'd turn up naked after the scarab dissolved the armour, and had to resort to stealing clothes from charity bins or that sort of thing. When asked what happened to his clothing when he didn't need it, he noted that it "just sort of dissolved". Most characters experience a bit of squick when they see the transformation.
Justified through an aversion in Captain Atom. When Nathaniel Adam transforms into Captain Atom, his clothing disappears, but usually reappears when he transforms back, except for the one time, in issue #8, that he transformed back into Nathaniel Adam involuntarily while unconscious. Then he was naked. The implication is that, without realizing it, Nate was using his matter-creation and manipulation abilities to recreate the clothes he was wearing when he transformed. Some fans have even inferred that Nate was recreating his whole body in this manner.
Although there is a scene from Justice League Europe showing Captain Atom transforming to his superpowered form, and it appears that the clothes were just pushed underneath the silver layer.
In ClanDestine, the immortal and invulnerable Adam Destine suffers extreme Clothing Damage every time he gets into a fight... but somehow, his pants always survive, albeit tattered. Under the circumstances, we must presume that A GenieDid It. Adam's son Walter Destine is not so lucky; his transformations destroy all his clothes except his underwear.
In earlier versions The Creeper has a device inside him that can make his costume reappear and disappear.
Kimo in recent issues of ElfQuest learns how to shapeshift into a wolf. When he's in wolf form he wears a bandana around his chest, but when he changes back to elf form it apparently slips down his torso to conveniently become a sarong.
In the Extinctioners comic, they literally are magic pants: team co-leader Phenix uses a spell to create "memory pelts" that swap places with whatever they're wearing when they say their code names.
All of the Fantastic Four usually wear a uniform made of "unstable molecules", so Johnny Storm doesn't burn his own clothes when using his powers. However, if he's wearing normal clothing, he will burn it away, shirt, pants and all. In the second movie, he complains about being asked to leave from Sue and Reed's rooftop wedding to chase the Silver Surfer, because "[he] just bought this tux!" Later, when their powers are swapped, Sue accidentally burns off her own clothing.
Sue hangs a lampshade on this — based on her being embarrassed at stripping to hide her powers in the first movie (of course, they turned off at the exact wrong moment) and her burning her clothing off at the second (again, turning back to normal at the exact wrong moment), she mutters "why does this always happen to me" as she turns invisible to hide herself from the crowd.
In the cartoon version of the Fantastic Four (where many outfits that the characters had worked with their powers) Sue comments about the pains for shopping for people "That can burst into flames" and "need to be able to stretch 300 feet in all directions". Thankfully in this series her power to turn invisible was applied to whatever she wanted it to.
And in comics, the formula's been stolen by at least one villain too, so knock-off designs are available to bad guys.
Unstable molecules are common in the Marvel Universe. Reed Richards apparently licenses the formula to the Avengers and the X-Men, among others.
The most obvious example is The Incredible Hulk, who seems to always wind up wearing those purple pants regardless of what Banner was wearing before the transformation:
In the live-action series, Ferrigno usually wound up wearing the same kind of pants that Bixby had on when he "Hulked Out". This led to amusing scenes in which the transformation would shred shirts, destroy heavy leather work boots, and even, in one case, crack open a motorcycle helmet — and yet those Magic Pants remained intact. One speculates that this was why the Hulk was so angry.
This was done to an even more ridiculous degree in the 1980s Hulk cartoon, where Banner's clothes spontaneously regenerated when he transformed back. (A side effect of Limited Wardrobe, probably)
In Hulk Vs., the Hulk is separated from Banner at one point, and both of them wind up with the Hulk's purple pants (the ones on Banner properly fitting him.) Huh?
Stan Lee once commented that he liked to work "science" (read: Technobabble) into all of his stories, and that Hulk's pants were the only time he never had a clue how the exact science behind it worked.
Another time he said that Mr. Fantastic (see bellow) gave Banner a pair of super-stretchy pants.
During the John Byrne run of She-Hulk, it was established that Jen's underwear never shreds during her transformations and fights because they were tagged approved by the comic book code. So no wardrobe malfunctions allowed here!
This even led Deadpool to believe there was some sort of power in the Hulk's pants, calling out "HULK PANTS, ACTIVATE!" while being held aloft by the Rhino. But, then again, Deadpool is a Cloud Cuckoolander.
Parodied in a billboard in Alan Moore's Top 10. "Super Stretchy Gamma Pants. You Wouldn't Like Me When I'm Naked."
A possible parody is the giant green dragon Fin Fang Foom, also in the Marvel universe, who wears purple pants.
However, this is subverted in the Ang Lee film, where there does come a point (after several stacking annoyances to Mr. Banner) where the Hulk is apparently completely naked. However, by this time he is largely shadow-clad.
In The Incredible Hulk film, Bruce Banner is shown buying extremely stretchy pants several sizes too big. Presumably he has quite a collection of belts.
In The Avengers, Banner is shown naked after transforming back into his human form. A kindly old night watchman ends up providing him with a new set of threads.
During Peter David's Hulk run, there was a gag where Banner found a line of purple pants similar to those worn by the Hulk. The clerk at the store mentioned that the pants were very popular with the obese due to their stretchy fabric.
Also lampshaded in an early issue of Wolverine. Hulk, in his "Joe Fixit" gray Hulk persona has shown up in Madripoor. Wolverine, being a longtime foe of the Hulk recognizes him immediately. In an attempt to scare Hulk off and play a gag on him, Wolverine breaks into Hulk's hotel room, steals his expensive custom-made Hulk-sized Mafia suits, and replaces them with many, many pairs of large, ripped up, purple pants. (Hulk then goes to a tailor he knows who does excellent rush work, and shows up at Wolverine's place fully decked-out in a white linen three-piece suit.)
Lampshaded and averted simultaneously in the Crisis CrossoverThe Infinity Crusade. Due to experiencing atmospheric re-entry, all of the Hulk's clothes burn off, plus he passes out due to the stress (though being Nigh Invulnerable, he was otherwise unharmed). After he lands on an opponent, a new hero unfamiliar with the Hulk wonders "if he always goes into battle in such a... natural state."
The Hulk's son Skaar has a magic loincloth, which shrinks to fit his human alter-ego.
Hulk's pants have been destroyed on rare occasion. In one instance revealing that he wore orange and yellow boxers that were apparently even more invulnerable.
One assumes the reason Bruce keeps buying this same brand of hideous purple pants is that they're so stretchy. Though why, in all these years, he's never asked Reed for some unstable molecule trousers is anybody's guess.
He did get a full tuxedo made of unstable molecules for a 2011 storyline that parodied about as many spy tropes as possible. The tux was destroyed by the end of the storyline.
When Iron Man's identity is first revealed to the Avengers, the villain literally melts his armour off leaving him in nothing but a red thong. This could also be female fanservice.
It happens again during the Marvel Adventures run. But this time he gets some boxers.
"Your only mistake was melting Iron Man's pants!"
This would happen to Tim Kelly of Kelly's Eye. In one example, Tim falls from space like a meteor. His space suit is burned away, but his shorts survive to preserve his modesty. See it here◊.
At least for awhile, if Marvel was going to avert this trope the most common victim would be Luke Cage. For some reason, clothing damage became a reoccurring issue for him.
Probably the earliest comic book example is Man O'Metal. When heat touched his body he would turn into metal and be surrounded by flames that could melt metal. His shirts always disappeared, but his pants (and shoes) stayed intact.
Martian Manhunter's short-lived series claimed that Martian clothing is actually a bioengineered organism that shapeshifts according to its wearer's telepathic commands.
Question: Do police officers pay for their uniforms, or are they provided by the precinct/city government/etc.? Considering how many uniforms Dragon went through in his initial career as a Chicago cop, plus the likelihood that they were custom-made for his muscular frame, his uniforms were a significant drain on either the city's budget or his salary.
Oddly enough, this usually happened when he wore street clothes. Word of God states that he would buy his clothes (no mention of his uniforms) from Big and Tall shops. Considering this version of Chicago is a City of Adventure, it makes sense that there would be a lot of them around.
There was one early issue in which he was changing in the police locker room and ripped his shirt simply by putting it on. He lamented that it was his last uniform that was fully intact. Another issue stated that he spends a lot of money buying clothes for this very reason.
One Story Arc of Spider-Man features a hero in training whose pants are not magic. His clothes get fried on multiple occasions, forcing him to trade up to a sturdier black leather version. (Not much later, he winds up suffering More Than Mind Control. Coincidence? Not likely.)
While the Lizard's iconic design usually includes a lab coat, it doesn't always — but he always at least gets to keep his pants.
In Uber, the American superhuman Colossus is shot with a tank shell to test his super-durability. The explosion blasts all of his clothes off – except, of course, his pants. Later, the Nazi "human battleship" Siegmund is attacked by dozens of Russian superhumans. The Russians' energy beams rip Siegmund's clothes to shreds and even sever one of his arms, but his pants and boots remain intact.
The Avengers' Wasp can alter her size, growing and shrinking at will. It isn't clear if she changes outfits so often because of the wear and tear on her clothing, or being a rich and fashion-conscious gal she just likes to mix it up now and again. However, an early panel does show her naked, , with nothing but a cheap cigar band hiding her virtue, furiously scolding someone (Hank Pym, presumably).
The Witchblade generally turns its wielder into a battle form covered with sort of Stripperiffic "armor", but while it can transform clothes, the exact fate of said clothes and the amount of generated Fanservice mostly depends on the specific wielder.
When the Dark Phoenix persona is bound by Professor X, causing her to revert to plain Jean Grey, her outfit vanishes, despite her costume having been her previous clothes, rapidly rearranged into that form a molecule at a time. (That was her main method of suiting up during the Phoenix era.) There's really no reason for it to have disappeared, and normally, No Ontological Inertia would cause the outfit to revert to its previous form (which would have been her Hellfire Club outfit) instead of vanishing entirely. Can we say Fanservice? In the Animated Adaptation, she shifts from the Dark Phoenix outfit to the normal Phoenix outfit instead.
In an inversion Mystique shapeshifts fully clothed, and it's eventually revealed that she doesn't wear actual clothes, but shapeshifts them. Presumably, the same goes for any such shapeshifter.
On several occasions, Made of Iron characters get blasted. Sometimes just enough clothing remains to keep 'em decent, and sometimes it's the ol' Censor Steam (which X-Men just loves.)
Husk, Paige Guthrie, has the ability to transform her skin into any material she can think of; but she must tear off the existing layer to do so. This results in her being naked a fair amount of time, but censor steam is not used in all scenes if her new skin serves the purpose of costume. She has specifically refused to revert to her human form on occasions because of her nudity.
There is also the short-time X-man Marrow, a woman whose powers were to have bone weapons (knifes, spikes, armor plates) growing out of her body, constantly sticking out of her clothes. Strangely, while her entire wardrobe consist of nothing more than what she is wearing, her costume never got ripped apart. Even more strange, some artist actually showed her bones ripping her clothes apart, but others drew these as if they were fused to her clothes. This even got topped when she got a Progressively Prettier upgrade giving her something that was called a bone bikini by readers, with her pink bodysuit sometimes appearing out of nowhere.
Dust's transformation may or may not leave her naked, depending on plot.
The detail around how Pixie wears tops changes by artist (then again her wings change by artist). In New X-Men it appears she wears shirts with a low back (room for her wings) but in another scene she's wearing a jean jacket (but we never see her from the back). In X-Infernus we see the back of her costume and the wings are just "there" with no sign of how she put on the outfit. In Uncanny she's shown wearing a completely backless shirt when her wings are broken, but she is later shown wearing another low back spaghetti string top like in New X-Men. There is another scene of her in Uncanny wearing her X-Men Yellows but we never see her from the back so there is no sign how the wings fit there.