The Samaritan got his name when he first arrived in the twenty-first century. After saving a crashing plane, he was swarmed by reporters and people thanking him, at which point he claimed he wasn't a hero, "just a good samaritan".
The Samaritan's Arch-Enemy Infidel took his name from the insult his enemies had hurled at him countless times across the centuries.
G-Dog got his name after he rescued some folks from being mugged; when they asked his name, Hank the Corgi immediately replied "G-Dog! I'm G-Dog!" (which was the term of endearment Hank's owner used).
Atomic Robo: Doctor Dinosaur got his name during his first encounter with Robo, when Jenkins burst in on him about to cut Robo to pieces over an insult, and declared it "some kind of doctor dinosaur?" Dinosaur had just moments ago been told by Robo his "given" name was utterly unpronounceable, and would just make people think he had something stuck in his throat.
The Avengers: The Vision got his name from a panicked remark the Wasp made on first seeing him, having been given no name by Ultron. Even after he turned good, he stuck with the name.
Vision: Perhaps I am what the Wasp called me... a Vision!
Avengers: The Initiative: Butterball, one of the most pathetic heroes of the Marvel setting got his name from a rather surly Taskmaster taunting him about his weight. Evidently it stuck and became his official name.
Bamse: Corrupt Corporate Executive Krösus Sork ("Croesus Vole") apparently adopted "Krösus" as his given name based on an ironic derogatory nickname in school (as The Un-Favourite, he never had any money). AFAIK, we have never seen his real name - but an earlier version of him was called "Sigge", so presumably he was Sigmund Sork or something.
Bane got his name after a warden called him one after he killed while still a child, in prison:
"He is a bane to everything holy!"
During his college days, Jonathan Crane would spend all his money on Psychology Books and thus dress shabbily, so his class mates would call him "scarecrow".
The Joker himself, according to The Man Who Laughs. This is initially what the media calls him, since they don't know anything about him except for his clown-like appearance — he loves the name and decides to embrace it.
In some versions of his origin, The Penguin took his alias from an insult the bullies at school used to taunt him with.
Batgirl: Year One retcons Batgirl's origin by stating Barbara Gordon got her name during her first encounter with Killer Moth. When the villain ranted over killing "Batman, Robin and Batgirl", she knew that she would always be "Batgirl" and not "Batwoman".
Killer Moth: This just gets better and better! I get to kill Batman, Robin and Batgirl, all in the same night! Barbara Gordon: (thinking) And so it became official. Now I am "Batgirl"... forevermore.
Big Bang Comics: Reid Randall created his blue and grey costume and equipped himself with a pair of nightsticks to defend his family's garment factory against mobsters who threatened to burn it down. Confronting them in the warehouse, one of thugs said "It's some kind of night watchman". Reid immediately decided to adopt that as his superhero name. Recalling how he and his brother used to play knights as kids, he announced "That's Knight Watchman...with a 'K'!"
In DC Comics, Booster Gold got his strange name when he flubbed his own intended name, "Gold Star", along with his college football nickname "Booster", when asked by Ronald Reagan.
Captain Mar-Vell made his debut when he stopped a killer robot sent by his own superiors in the Kree army that was sent to Kill All Humans. During the battle the robot kept addressing him by his rank and name "Captain Mar-Vell". Bystanders misheard and assumed that Mar-Vell was a new superhero named "Captain Marvel". Mar-Vell decided to go along with it. Used again with his Ultimate Marvel incarnation, Marh-Vell. When interrogating him, Carol Danvers hears his name as "Marvel", and thinks he's a new superhero (and a Native America to boot). In fairness, with his armour, he does look like a superhero.
Daredevil was a mocking name Matt Murdock received back in school for not playing sports. Later parodied in a Mini Marvels comic.
Marvel superhero Darkhawk got his name from a crazy old hobo. Before that, he'd seriously been considering calling himself "Edge-Man".
The Ur-Example with the DCU was the entire, original Doom Patrol. The press gave them superhero handles, which they initially rejected as "freak names," but eventually embraced. (Though they never called each other by those names.)
Fables: Bigby was nicknamed The Big Bad Wolf by his bullying brothers as an insult because he was tiny as a cub. He grew up to be big and powerful and took that name for his own.
The original Flash, Jay Garrick, got his name from a passing remark his girlfriend's dad made. Up until then, he hadn't bothered calling himself anything while superheroing.
The Silver AgeFlash gained his name when a reporter interviewing him noted Central City's mysterious new hero "sure caught that guy in a flash...what did you say your name was?" Barry responds, "you just said it—the Flash!" It helps that Barry also idolized the Golden Age Flash, Jay Garrick. Earth 2 paid homage to this, when that world's version of Jay Garrick uses his newly-gained super speed to save a young couple from some Rodents of Unusual Size, saying he'll do it "in a flash". Since he's moving at super-speed, they don't properly hear him, but they do pick up on the word "flash", which they recount to a news crew. Ergo, Jay calls himself The Flash.
According to The Further Adventures of Cyclops and Phoenix, X-Men enemy Mister Sinister got his name from the curses of his dying wife. Appropriately enough for a guy who became a supervillain in the 1800s, you don't get more gothic than that.
Great Lakes Avengers: In her debut, Good Boy got her alias when a couple of villains started attacking her neighborhood. She confronted one of them, who, upon watching her transformation into a werewolf, realized he had stepped in it and could only reply, "Uh—g-g-good boy?"
In The Wonder Year, Oliver Queen gets dubbed Green Arrow when a stoner drug dealer he busted on his first outing gives a TV interview in which he refers to "this big, green arrow dude" who came out of nowhere.
In his Golden Age Of Comic Books origin, "Birth of the Battling Bowmen" in More Fun Comics #89, when Ollie and Roy Harper first meet and use their archery skills to stop a gang of criminals, one of the crooks says "Golly, that kid's speedy" and another says "Watch out for the big guy, he shoots a mean, green arrow". The two start using these as nicknames for each other, and adopt them as heroic identities at the end of the adventure.
Ollie: And we've been fighting ever since, Roy, under the names those thugs unconsciously gave us.
Hunter's Hellcats get their nickname from a comment made by a guard as Lt. Hunter is leading his new recruits out of the stockade:
Guard: Don't turn your back on 'em, sir! Those hellcats are the dirtiest lot we've ever had! Hunter: Hellcats, huh? Maybe the Japs will find that out, too!
Hawkman villain Ira Quimby was called IQ by his criminal associates not only because of his initials, but as an ironic statement about how stupid he was. When he discovered a trinket that gave him incredible intelligence, he decided to keep the name.
It's often said that Batman gave Bart Allen the codename "Impulse" as a warning. This is actually a retcon; he created it himself during Zero Hour: Crisis in Time! (though all-but-confirmed in his second appearance a month before and reinforced a few issues later in the main Flash ongoing), a fact even his creator forgot.
When Bruce Banner first turned into the Hulk, nobody else realized, besides Rick Jones. And so, a superpowerful being of unknown name and origin destroyed the military base while leaving it. The soldiers deployed to locate and kill the creature, and one unnamed soldier said, "We've got to find that... that hulk!!"
Similarly, when Betty Ross first saw the Gamma-transformed Emil Blonsky, she described him as "some kind of... abomination!" Guess what his supervillain name became...
The Heroes RebornContinuity Reboot attempt had the Hulk and Iron Man do this to each other when their origins were mashed up into a single storyline. (Tony used the H-word when he first saw the mutated Banner, and the Hulk liked the sound of it; the other side was just applied Hulk Speak.)
In Immortal Hulk, the titular new alter initially just goes by Hulk. It's only during his fight with the Avengers when he overhears Thor remarking on his nature that he identifies himself.
Hulk: Hh. 'Devil Hulk'. Works for me.
Invincible: The titular character got his name from a conversation with the school counselor who told him "You're not invincible."
Judge Dredd: When the man once known as Judge Sidney shocked even his fellow Judges with his tendency towards executing every single offender brought before him, they called him "Judge Death" as an insult. The Judge subsequently took the name for his own, and lived up to it. Of course, given that he started as Sidney De'ath, this wasn't much of a leap.
The Life and Times of Scrooge McDuck: The Beagle Boys evolve from river pirates to who they are today, except they had a bit of trouble naming their group — throughout the comic they considered naming themselves "the Mardi Gras Gang" (their employer, Porker Hogg, got their masks from said event), "the Dirty Double-Crossing Dogs", and "the Masked Marauders". Eventually, when Scrooge tricked the gang and saved the day, he announced to the nearby government ship, who came to investigate, "These are the awful Beagle Boys!"
Beagle Boy 1: "The Beagle Boys"! Catchy! Simple, yet elegant! Beagle Boy 2: Not bad! Rolls off the tongue!
MAD artist Don Martin created Captain Klutz, whose name derived from the insult ("You Klutz!") of a robber he captured by accident. (Young Ringo Fonebone had actually been attempting suicide when he landed on top of the fleeing crook.) When a police Captain asked for his name, the dazed Fonebone replied, "I'm a Klutz, Captain." Perhaps not a pure example, as Fonebone was briefly amnesiac, and actually thought it was his real name, at least at first.
The New Warriors got named when a random reporter referred to them that way, and Night Thrasher hurriedly announced they'd be sticking with that before any of his team could come up with anything more embarrassing.
Modern age Plastic Man got his name from flubbing "Elastic Man", also when asked by a reporter. This is actually a retcon; when the character was created in the 40s, "plastic" was more commonly used as an adjective, before it became more commonly associated with the material "plastic" (so called because it is, of course, plastic - able to be deformed into other shapes). There is a song by The Fall called, "How I wrote Elastic man"; in one verse it says "How I wrote elastic man" and ends with "How I wrote Plastic man" Coincidence?
Arseface from Preacher, after hearing Cassidy say he has "a face like an arse" and then seeing his father shoot himself. He takes up his new moniker in a straight send-up of many classic scenes:
- "Uh wuh huh vuhhyuh uh Juhh Cuhh! Vuhhyuh fuh uh bluh uh muh fuhh! Uh uh uh huh uh fuh luh uh uhh — suh buh uh! Uh wuh becuhh Uhhfuhh!" (I will have vengeance on Jesse Custer! Vengeance for the blood of my father! And if I have a face like an arse — so be it! I will become Arseface!)
In PS238, the Most Common Superpower isn't big boobs, it's F.I.S.S.. Cute Bruiser Julie is the eighty-fourth of these documented and as such feels a little inferior until she gains some confidence. She then registers "84" as her official hero name, possibly because Moon Shadow was the first one to call her that.
In Punisher Noir, Detective Martin Soap nicknames the mysterious vigilante who's been wreaking havoc on the Manhattan underworld "The Punisher", after a popular radio drama he theorizes inspired the man. He's partially correct — our protagonist took a few pages from his favorite radio show when he started his Roaring Rampage of Revenge, but he never really had a name for himself before he heard the one Soap gave him.
A member of Sgt. Rock's Easy Company was mockingly called "Ice Cream Soldier" — he was inexperienced and notorious for both "melting down" (panicking) and "freezing up" in tense combat situations. He adopted the name proudly after he saved the whole company from two oncoming German tanks during a heavy snowstorm, and it came to refer to his new cool demeanor and comfort in cold weather.
Shazam!: Captain Marvel first got his nickname, Big Red Cheese, from his Arch-Enemy Dr. Sivana, but it was quickly adopted by both his friends and his fanbase.
Subverted in Supergirl: Cosmic Adventures in the 8th Grade. A reporter asks Kara if she is some kind of Supergirl. Later she chooses to call herself Supergirl, but she gave no indication she got her name from that random reporter.
"The Unknown Legionnaire": Since the masked hero will not tell the Legion of Super-Heroes his name, Cosmic Boy decides to call him Unknwon Boy for the time being. Since he has not his own identity, the mysterious hero has no issue going by that nickname.
The 80s reboot has Superman get his name when Lois Lane writes an article about a mysterious "Superman" who saved a flying aircraft.
The Death of Superman: Booster Gold gave Doomsday his name when, after Superman caught an airborne Booster, he mentioned that "It was like Doomsday is here!" When Superman confronts him, he says "What did you call him? Oh, yeah: Doomsday."
In The Transformers (IDW), the term "Autobot" originated as an insult directed at all Cybertronians. Orion Pax started a movement to reclaim it, and it ended up being used for Sentinel Prime's and Zeta Prime's security forces; when the Decepticon movement began Jumping Off the Slippery Slope, Orion Pax - now holding the Matrix of Leadership and calling himself Optimus Prime - formed the heart of his army from those security forces.
Ultimate X Men: The names that the mutants use, both on Xavier and Magneto's side, are a new naming system of their own design, that names them after their mutant abilities rather than after an ancestor.
Ultimate Mysterio explained it this way: "'But you can keep calling me Mysterio. I like that. I would have never come up with that name myself but it's out there now... and I like it.'" This may have been a ruse by Ultimate Mysterio, who was revealed to be an android controlled by the mainstream Mysterio.
Also Spider-Man himself. He needed a stage name in the wrestling arena, so he chose the name "The Spider". The announcer fixed it on the fly, and gave him the name "Spider-Man". Peter complained for a moment, but then he liked it.
Unstoppable Doom Patrol: Degenerate calls himself that because that's what the people at Metagen called him.
Watchmen: Hollis Mason was given the sarcastic nickname "Nite Owl" by a co-worker irritated by Mason's early bedtime. At the same time, he was looking to become a "costumed adventurer," but was stuck for a name...
"'Nite Owl.' I liked it. Now all I had to come up with was the costume."
