Captain America had a bare neck in his first appearance, and used a triangular shield rather than his more recognizable circular one (which was changed so that he didn't look like The Shield). This design has sometimes been used in subsequent stories to show his beginnings, with the explanation that his gear evolved In-Universe. note John Byrne later explained that Cap's mask had been knocked off in a fight and his secret identity was almost exposed as a result. To fight that, he modified the mask to connect to the rest of his costume, which had the added benefit of covering his neck with additional armor.
In Captain America Comics #1, Cap's costume does not have a star on his back, and the red and white stripes on his lower chest extend around his back. From issue #2 onward through his 1950s appearances, he does have a star on his back, but the stripes only appear on the front of his costume. When he returned in The Avengers #4, he had both the star and stripes on his back, which became the standard. The stripeless back was later Retconned into being his earliest design (at first paired with the bare-necked mask), and was the version of the costume that was duplicated by William Burnsidenote who is a Retcon himself, assuming the identity of Steve Rogers during the 1950s and becoming the "Commie-Smasher" Cap of that era, while the Silver Age version has been used in all subsequent stories set in World War II save for Steve's earliest adventures as Cap.
The Falcon's costume was originally green rather than red, and didn't have wings, just a grappling hook.
During her first appearance in Ed Brubaker's run, Janice Lincoln, the new Beetle, was clearly a white woman. Her expanded role in The Superior Foes of Spider-Man would later reveal she was the Afro-Dominican daughter of Tombstone, and her skin was darkened to reflect this development.
The Thing had a very lumpy, uneven orange hide for his first few appearances. Jack Kirby gradually evolved the character's design over the ensuing issues, until he finally settled on the iconic, rock-like look the character is best known for. This evolution has been acknowledged in-universe, particularly when Sharon Ventura, the second Ms. Marvel, became the She-Thing, and had the same lumpy definition at first.
The Golden Age Human Torch was originally drawn as a human-shaped blob of flames, before his design was refined so that his physical body was clearly outlined, with largely vertical black lines to define his musculature. When Johnny Storm became the new Human Torch, Kirby initially drew him with an even more vaguely human-shaped blob of flames than the original Torch in his earliest appearances. Kirby soon updated Johnny's appearance to the "classic" Torch design, but made Johnny's facial features visible to distinguish him from the earlier Torch.
Uatu the Watcher originally had visible pupils instead of Monochromatic Eyes.
In his very first appearance on the final page of Fantastic Four #48, Galactus wore a bizarre red and green costume with exposed arms and hands, rather than his more familiar purple armor. The purple color scheme was implemented in the very next issue, but the outfit still had exposed hands and bare legs for some reason. He wouldn't get his iconic design until Fantastic Four #74.
Lockjaw of The Inhumans had completely different (and noticeably longer) antennae in his very first appearance. Crystal, meanwhile, initially had a fairly generic white dress rather than her more memorable yellow superhero costume.
While the top of Namor's head often looks flat, his Golden Age adventures sometimes had him drawn with a large, exaggeratedly triangular skull that made him resemble an alien. His green trunks were also variously colored red, black or blue depending on the issue, which continued into the early Silver Age. The other members of Namor's race also looked completely different in the earliest stories, with large, bulging eyes and fish-like appearances. This was gradually toned down until they came to resemble humans with blue skin instead.
In his first appearance as a costumed superhero, Ant-Man’s boots and gloves were purple rather than blue. Also, the Giant-Man costume initially sported a circular chest emblem similar to the one on the Ant-Man suit, but this was quickly ditched in favor of a pair of stripes running down the torso. The original chest emblem was revived years later for Giant-Man’s design in the Avengers: Earth’s Mightiest Heroes cartoon.
Moon Knight originally wore a glider cape that was attached to his wrists, which was eventually done away with in favor of a more traditional cape.
In the original Bloodstone mini-series, Elsa Bloodstone had long blond hair that she sometimes wore in pigtails, and her wardrobe consisted of skimpy explorer outfits that seemed inspired by Indiana Jones and Tomb Raider. Her design was completely overhauled by Stuart Immonen in Nextwave, with her hair color changed to red and now being worn in a Tomboyish Ponytail. She was also given a Badass Longcoat, which would quickly become her signature garment.
Famously, Daredevil wore a bright yellow bodysuit with a dark red/black (the coloring seemed to vary at times; it may have been intended to be brown) tunic for the first six issues of his original series.
The target logo on Bullseye's mask was far larger and more prominent in his first appearance. Once Frank Miller began drawing the series, he made the logo smaller and placed it more directly on Bullseye's forehead.
Thanos was much skinnier in his first appearance, and wore a sleeveless, bare-legged costume that looked similar to the one worn by Darkseid.
Starfox and his father originally had purple skin in their debut, implying this was true of all Titanians. They were soon changed to have the same skin color as Earth humans, leaving the purple skin to be a unique trait Thanos possessed due to his Deviant genes.
When Tiberius Stone was first introduced in Iron Man, he was handsome, athletic, fashionable, and blond. When he joined the cast of The Amazing Spider-Man (Dan Slott), he was redesigned to have darker hair, a scrawny build, and a nerdy fashion sense.
Speaking of Iron Man, the original armor was very bulky and gray, and lacked the sleek build and bright colors of the later suits. The classic red-and-gold suit also went through a couple different facemask designs (the "horned" mask and the riveted mask) before settling on its classic design (the short-lived nose came much later).
Tony's hair color varied for a while too, being alternately black, brown or red before settling on the former. Pepper Potts also looked different originally, being modeled after Ann B. Davis (who had played a secretary on The Bob Cummings Show), with brown hair in a bun and a freckled face.
Fin Fang Foom was colored orange in his first appearance, which was odd, since he was green on the cover.
The Hulk was gray in his first appearancenote According to Stan Lee, "Well, my first choice was gray 'cause he was a monster, he was supposed to be scary and I figured gray might be a scary color. But there was a problem. When the book was printed, the printer had trouble keeping the color consistent. So I had to use a different color and I figured green, no superhero I knew wore green at the time. So I said, 'Okay, let's color him green.' It was as casual as that.", and wasn't nearly as large as he would later become. This is long before the distinct "Gray Hulk" would be introduced as another split-personality form of the Hulk; the original was very much the primary "Savage Hulk" persona, just without the green skin. He also had a flat, Frankenstein-like head and a very prominent brow in these early issues, and sometimes wore very small trunks that resembled a speedo, rather than his trademark torn up pants. Additionally, the character had an ever-changing number of toes. When he first appeared, Hulk had five toes, but when his book was cancelled and he resurfaced in Fantastic Four, he now had three. When he joined the Avengers, he then had four, but went back to three by the second issue, only for this number to vary wildly in each subsequent appearance before the artists finally settled on five in Tales to Astonish. This was the subject in a Mythology Gag in Ultron Forever, where the Hulk transported from the past still had three toes.
Doctor Strange didn't have his trademark Cloak of Levitation in his first appearance. When he did finally get the cloak, it was actually colored blue instead of red for about the first year of its existence. Strange himself started out looking much older than his eventual appearance, with slanted eyes and vaguely Asian features as well.
Amatsu-Mikaboshi had a very minimalistic design in his first appearance in Ares' miniseries, basically just a Japanese monk outfit. When he reappeared in the pages of The Incredible Hercules he gained a more elaborate design, complete with golden headdress, more befitting of an evil god. His hair also became brown (it was black before).
The horns on Magneto’s helmet were much more prominent in his early appearances. Also, his guest appearance in Amazing Adventures #9 depicted him with wavy brown hair, while all future appearances would go with the white hair he previously had in X-Men #62.
In his first few appearances, Quicksilver sported a green outfit with tights that were worn under a tunic with shoulder pads. When the character joined The Avengers the following year, his costume was redesigned into a sleeker bodysuit, which he would wear for the next few years. His iconic blue and white costume would not debut until Avengers #75, and would subsequently remain his most notable and recognizable outfit to this day.
Similarly, Scarlet Witch's original headdress looked more like a wimple, albeit one with an opening that exposed her hair. Like her brother, she was later given a slight redesign after she joined the Avengers, with the wimple being abandoned in favor of her signature tiara.
Beast originally looked like an ordinary human, albeit one with enlarged hands and feet. He didn't gain his iconic apelike appearance until the Amazing Adventures series in The '70s, and even then, his fur was initially gray, then black, before finally being described as blue in the pages of The Avengers.
In the very first issues, Iceman had a rather grotesque appearance analogous to the Thing, like an animated snowman with visible black boots. He dropped the boots starting with X-Men #5, and then gradually shifted to his more familiar ice cube look. This could be explained as him becoming more skilled with his powers, since he uses them to create his "costume".
The original Sentinels had a different color scheme, and were much smaller than the Humongous Mechas most fans are familiar with. What are now called "Sentinel MK I" introduced in 1965 were only about the twice the size of a human and had blue torso, hands and feet, red arms, legs and heads, and orange faces. 4 years later the Sentinel MK II established the three-tone purple look that all "regular" Sentinels have stuck to ever since.
After the X-Men ditched their matching uniforms and got individual costumes for the first time in issue #39, Angel started wearing a bizarre yellow suit with a blue mask and red suspenders. The new outfit proved unpopular, and was eventually done away with in X-Men #62, where Angel was given a new blue and white costume with a halo symbol across the chest. This quickly became Angel's best known design, with many of his later costumes being slight variations of it, such as the red version he wore during Chris Claremont's Uncanny X-Men run and during his time with The Defenders.
Most of the new costumes from issue #39 fall under this trope. The new design for Cyclops was well received and became his default look for many years, but none of the others had quite as much staying power. These included Beast wearing a red and blue bodysuit with a mask similar to the one on the old uniforms, and Jean Grey donning a miniskirt with a mask and go-go boots. Of note, the green and yellow color scheme would later be used for her Phoenix outfit, and the go-go outfit would go on to reappear several more times throughout the character's history, including the end of The Dark Phoenix Saga and during Jonathan Hickman's run.
Havok has brown hair in his first couple of appearances. He quickly switched to blond, though.
Banshee originally had an unattractive, almost apelike face during the 60s, but was eventually made more conventionally handsome once he officially joined the X-Men during the 70s.
The ears on Wolverine's mask were originally far smaller when he first showed up in The Incredible Hulk, and Logan himself was less hairy. His eyes could also be seen in his first appearance (rather than featureless white) and the mouth has a ridged line design that was scrapped by the time he showed up in Giant Sized X-Men. He was also originally taller, appearing to be around 5'5 instead of 5'2.
Apocalypse was fairly lean in his early X-Factor appearances, in sharp contrast to the Large and in Charge design most fans associate with the character.
When Rogue first debuted in the pages of The Avengers, she had a more homely appearance and was visibly older than her actual age. She was only redesigned to look younger and prettier once she became a member of the X-Men. Her hair was also shorter originally before becoming longer and wavy (ironically the opposite process occurs with her rival/foil Carol).
Gambit had pretty different look when he first appeared to a de-aged Storm in the 90s. Firstly his irises were white rather than red and his face was creepy and long (Claremont had initially intended him to be secretly a younger Mr.Sinister who would be a Evil Mentor before changing his mind) upon joining the X-Men Gambit gained the dashingly handsome and chiseled look he’s known for. Not to mention the cover depicts him as having purple thighs with stripes along with blue full gloves and boots almost none of which was used proper.
Jubilee had an entirely different design in debut wearing a blue jacket, black shirt and blue skirt. It wasn’t until until issue #257 that she got her yellow trench coat that’s stuck with her decades as well as her shades, though the blue shorts and gloves wouldn’t come until later on when she joined the X-Men proper as they were green making her similar looking to Robin.
Sabretooth's first costume lacked the character's signature headpiece. Additionally, while Sabretooth himself was still pretty beefy, he wasn't quite as massive as he would later be drawn as.
Silver Samurai looked completely different in his debut, sporting a bizarre silver and blue costume with buccaneer boots, exposed legs and a helmet crest that resembled a mohawk. He would be completely redesigned for his next appearance, with the new costume being what he's stuck with since.
Moondragon's costume was red rather than green in her first appearance.
Black Panther had a cape in his first appearance, which was quickly dropped in later issues. The cape does still show up from time to time, but usually as a ceremonial piece more than anything. When he first joined The Avengers, he also sported a half-mask that exposed his mouth and chin, which was done away with after a few issues.
Black Widow originally had black hair, and wore a much more flamboyant costume that included a mask, fishnets and a cape. Natasha would bring the costume back years later just to tease Tony Stark at the end of a mission in Russia in an issue of Iron Man. Not to mention her very first outfit as a Femme Fatale Spy which was a green dress, scarf and hat.
In The '70s, Blade was drawn in a positively groovy green outfit with oversized sunglasses and a funky looking afro. His badass leather ensemble only began to take shape in The '90s, before being solidified by the 1998 movie.
During Steve Ditko's run, the wall-crawler had noticeable, dramatic webs under his armpits. These mostly disappeared over time as other artists took over, to the point most people don't know they were ever part of the costume. He was also incredibly skinny, to the point he almost looked malnourished. When Ditko left, so did the Geek Physique. As well, his first appearance had the large spider on his back be blue. All subsequent appearances would turn it red. Peter also had blue eyes and kept wearing his glasses for the first handful of issues before ditching them. Another detail that is easily missed was that in his first issue Spidey appeared to have eye holes or at least visible pupils in his mask, whether it was a mistake or intentional choice to empathise the moment is unknown but either way, Peter’s eye lenses never show his pupils like that again.
Doctor Octopus wore a white lab outfit during his first appearance in The Amazing Spider-Man (Lee & Ditko) #3, followed by a very plain purple outfit when he returned in issue #11. His iconic green jumpsuit didn't debut until issue #53, and even then, it lacked the yellow collar, gloves, and boots, which wouldn't be added until issue #88.
Gwen Stacy in her first appearance is very dissimilar to the iconic look she’s known for nowadays. No Brigitte Bardot headband, green jacket, or purple skirt (which were her death clothes) she’s instead she had pinned up hair and a red dress as well as arching eyebrows which went along with her haughty Alpha Bitch introduction. It wasn’t until John Romita Sr. showed up that Gwen’s features softened and by The Amazing Spider-Man (1963) #47 her signature headband showed up. The green coat would come even later when she started dating Peter.
The Vulture had tail feathers on his costume in his first appearance in The Amazing Spider-Man (Lee & Ditko) #2, which were dropped for his subsequent outings.
In his debut appearance in The Amazing Spider-Man (Lee & Ditko) #300, Venom lacked his razor-sharp fangs and long, bestial tongue. Instead, Venom donned a prominent Slasher Smile with regular human teeth and looked less monstrous overall.
In his first appearance in Ultimate Marvel Team-Up, Iron Man had a completely different armor that looked more akin to his mainline universe suits, rather than the blockier, bulkier design he would later sport in The Ultimates.
In her Early-Bird Cameo in Captain Marvel #14, Kamala Khan looked older and had a different hairstyle. She also had an overall more feminine personal style (complete with lipstick), which would seem at odds with the more Tomboyish fashion sense Adrian Alphona ended up giving her in her solo series. According to G. Willow Wilson, this is because the Captain Marvel artists were working off of a generic description of the character, and didn't yet know what her finalized design would look like.
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