Meaningful Rename / Western Animation

• Arcane: Given that Jinx of League of Legends is introduced in the show as Tag Along Kid Powder, it's a Foregone Conclusion that something dramatic has to happen to cause her to change her name. Her older adopted brother Mylo calls her a jinx for her bad luck initially, which she resents. It takes Powder accidentally killing most of her adopted family for her sister Vi to condemn her as a jinx as well. Powder being seemingly abandoned by Vi and then her subsequent adoption by Silco causes her to adopt Jinx as her new name, accepting her destructive tendencies.
• The second season of Infinity Train focuses not on Tulip (who got her number down to zero and went home) but on her reflection (who was freed from the Chrome Car). The reflection of Tulip does their best to distance themselves from her, changing their clothes and hair, but don't choose a name until the end of the season. She chooses the name Lake, as a lake was the first part of the real world she ever saw.
• The Owl House: Raine officially rebrands the Bards Against The Throne as Covens Against the Throne, since it now includes not only the founding bards, but also witches from other covens.
• Happens a LOT in the various incarnations of Transformers, due to upgrades, new altmodes, new continuities...
  • Probably the most famous is Hot Rod becoming Rodimus Prime in the movie upon opening the Matrix of Leadership.
  • Megatron becoming Galvatron. In the first instance (The Transformers: The Movie) it's up for debate as to whether he's even the same person as Megatron.
  • In that vein, many recolored versions of the same toy are marketed as upgraded versions even if they never appeared in the show, occasionally with five-sentence backstories explaining why they're a different color.
  • The original cast of Beast Wars was implied to have taken their known names around the time they got stranded on the planet. Most of the names are references to their new beast modes, but the captains - "Optimus Primal" and "Megatron" - instead take names after the Generation One leaders. (Or, alternately, Megatron takes his from Cybertronian scripture, suggesting the G1 Decepticon did the same.)
    • Rampage was known as "Protoform X" until he was Made a Slave by Megatron, who renamed him. He would later admit that the new name suited him.
  • Orion Pax becoming Optimus Prime, though he generally has this change made for him, rather than being the one who decides to make it.
    • The Aligned continuity puts a spin on this, in which it's revealed in the Covenant of Primus that Optimus Prime is the real name of "Thirteen," the last of the thirteen original Primes created by Primus. After the Fall of the Primes, he willingly entered the Well of Allsparks so that he may be reborn as an ordinary Cybertronian in order to better understand the needs of the next generation. It then reveals that he was reincarnated into Orion Pax. When the humble data clerk Orion Pax accepted the Matrix of Leadership, he regained his memories as one of the thirteen original Primes, and retook his name as Optimus Prime.
  • When Optimus Prime rescues and rebuilds several Autobots after his own resurrection, Bumblebee checks out his updated form and comments that he's "like a new gold bug." Optimus decides that Goldbug will be his new designation to go with the new body.
• Skips from Regular Show always skips rather than walking. It turns out his real name is not Skips, but Walks. He changed it because he got tired of everybody asking him why he skipped everywhere instead of walking. Or, at least, that's what he says at first. A later episode shows the real reason: It was the name he chose when he was reborn as an immortal as his way of memorializing the woman he loved, who he always skipped with.
• In an episode of South Park, after acquiring the last Plot Coupon in her quest, Barbra Streisand announces her transformation into a Humongous Mecha by saying (in Japanese) "From now on, my name is... Mecha Streisand!"
  • In the Documentary Episode "I Should Have Never Gone Ziplining", when the boys' attempt to escape the ziplining tour ends them up in a horseback riding tour, the show becomes "I Should Have Never Thought Horseback Riding Would Be Any Better Than Ziplining". When the boys decide to ditch that tour in favor of a boat ride for themselves, it becomes "I Should Have Never Got on a Goddamn Boat".
• SpongeBob SquarePants: At the very end of "Jellyfish Hunter", the blue jellyfish referred to as "Ol' No-Name" by SpongeBob lets itself get caught, allowing SpongeBob to rename it "Friend".
• Nobody Smurf in The Smurfs (1981) gets one in the form of Somebody when he rescues his fellow Smurfs from the evil prankishness of Mystico the goblin.
• My Little Pony: Friendship Is Magic:
  • Nightmare Moon fits this fairly well, as Princess Luna was known by this name after becoming a Fallen Angel. Assuming they're actually the same individual; one of the tie-in comics portrayed it as full-on Demonic Possession, although their canon status is uncertain.
  • According to "The Perfect Pear", the Apple siblings' mother used to be called Pear Butter but changed it to Buttercup (the Affectionate Nickname given to her by Bright Macintosh when they first met) after marrying into the Apple family. Also, Chiffon Swirl changed her name to Cup Cake when she married Carrot Cake.
  • It's quite common when turning evil, with Fizzlepop Berrytwist calling herself Tempest Shadow, and Twilight Sparkle calling her evil alter-ego "Midnight Sparkle" in the Equestria Girls spinoff.
  • In one shared nightmare between Princesses Celestia and Luna, Celestia's fallen self has renamed herself "Daybreaker".
• Garfield and Friends: A Show Within a Show featured a host named Fred Gazorninplat. Garfield told Odie the host changed his name to take the job and previously went by the name Sam Gazorninplat.
• The Teenage Mutant Ninja Turtles series has the Battle Nexus' Daimyo's son, who gives himself the title of "The Ultimate Ninja" after he (wrongly) believes he's defeated Leonardo in mortal combat. However, since he like all the Battle Nexus natives has no actual name, this is less a case of someone renaming themselves than it is a case of naming themselves period.
• The Simpsons: Homer tried to do this when he changed his name to Max Power for one episode. (He also tried to get Marge to change her name, giving her the options Chesty La Rue, Busty St. Clair, or Hootie Mcboob).
• Avatar: The Last Airbender has a Genius Bonus in how all of the writing is actual Chinese writing and can be translated. In season one, Zuko's name was written with the characters for "resurrect rule" or "revived law". When he became a fugitive in season two, his name on the wanted posters was written with the characters for "ancestor robber", which is meant to be insulting. In season three, when Zuko is once again seen as good by the Fire Nation, his name is written more flatteringly again.
• My Life as a Teenage Robot: XJ9 renamed herself Jenny in her desire to be accepted as a teenager instead of being treated as a machine. Nora sticks to calling her XJ9 but will call her Jenny during a heartfelt moment.
• The Spectacular Spider-Man sees Fancy Dan take up the name "Ricochet" after gaining Powered Armor. Ox decides to still keep the same codename and Shocker is still called by his nickname "Montana" out of costume.
• Baby Looney Tunes: Once when Daffy made fun of his name, Bugs started to go by the name Bruce.
• In Peter and the Magic Egg, Tobias Toot renames himself Tinwhiskers after he turns himself into a machine.
• She-Ra and the Princesses of Power:
  • "In the Shadows of Mystacor" reveals that in the past, Shadow Weaver used to be called Light Spinner. She changed her name when she made a Face–Heel Turn and joined the Horde.
  • In "Destiny, Part 2", viewers learn that Hordak initially did not have a name, being a mass-produced clone soldier in Horde Prime's army, and that "Hordak" was what he named himself after coming to Etheria. Horde Prime expresses disgust when he points out that Hordak had given himself a name.
• Tangled: The Series puts quite a lot of emphasis on character's chosen names, and what it means to them to be referred to as such.
  • Eugene insists on being called Eugene, and any other character refusing to abide by this in lieu of his old name, Flynn Rider, is normally a sign that they're not an ally or otherwise trustworthy person. When a character stops referring to him as Flynn Rider and begins calling him Eugene, this usually signifies a completed Heel–Face Turn from an enemy into an ally.
    • Season 3 episode "Return of the King" reveals that Eugene's real birth name is actually Horace. Like as with other characters, Edmund's insistence on calling Eugene by this name illustrates the tension between them and Edmund's unwillingness to accept Eugene for who he is. By the end of the episode, Edmund has come around and started using his son's preferred name, pointing to a huge positive development in their relationship.
  • Similarly to Eugene, Lance identifies with his chosen name and gets upset when referred to by his birth name, Arnwaldo Schnitz.
  • The two thief sisters befriended by the main cast refuse for the first two seasons to tell anyone their real names and are instead referred to as "Angry" and "Red," the nicknames given to them by Eugene and Lance, for the duration of this time. In Season 3, when "Red" is struggling with constantly feeling overshadowed by Angry and tired of not being listened to, she refuses to go through with the ritual to cure her lycanthropy and breaks down, yelling that she never even liked the nickname "Red" and just went along with it because that's what everybody else wanted to call her. She transforms into her monstrous wolf form and runs off into the forest in a rampage. The only thing that is able to calm her down is her sister apologizing for not recognizing her emotional needs and finally opening up to the rest of the cast (and the audience) by calling her by her real name.
  "Angry": Catalina, are you there? It's me, Kiera.
• He-Man and the Masters of the Universe: Keldor's face was melted off by acid. Hordak saved his life at the cost of his head now being a skull floating above his shoulders. Hordak then declared his new name is Skeletor and he accepted it.
• Masters of the Universe: Revelation: Evil-Lyn reveals that her birth name is just "Lyn", but she changed it when she joined Skeletor and became a villain.
• The Amazing World of Gumball: In Season 2, it's revealed that Gumball is just the main character's nickname, and in Season 3, he discovers his real name is Zach, he quickly becomes an arrogant Totally Radical jerk, but then it's revealed that Zach is his alternate personality who is taking over, who is also changing his memories to turn Gumball's past failures into victories, Gumball has a fight against Zach in his mind, Gumball wins and erases his evil personality, and the episode ends with him legally changing his name into Gumball.
• Kim Possible: Played for Laughs when Gil is mutated into a Fish Person and declares that his name is now "Gill" with two "L"s.
• In Central Park, Season 1 "A Fish Called Snakehead", when Bitsy meets Mayor Whitebottom's likability consultant, Ashley, she reveals her previous name was Debra but changed it because, according to her, nobody likes a Debra.
  Helen: My mother's name was Debra.
  Ashley: And?
  Helen: Hmm.
• Downplayed in the Molly of Denali episode "Sassy Ladies On Ice." The Sassy Ladies drop the "of Saskatoon" part of their name when they invite Molly and Layla, who don't live in Saskatoon, to officially join.