Lady Mondegreen

A character or non-character in a show, named (and celebrated) by fans after a line they misheard.

Not to be confused with the supervillain/Evil League of Evil applicant who thrives on the trope. Also not to be confused with Mondegreen, which is something different despite sharing an origin and half a name.

Newspaper Comics

 * In one Peanuts story arc, Sally tells Charlie Brown about her role the upcoming Christmas play, in which she's supposed to say "Hark!", "then Harold Angel sings." Charlie Brown assumes she misunderstood the lyrics, but it turned out that one of the other cast members really was named Harold Angel.

Fan Fiction

 * The author of Pretty Cure Perfume Preppy canonically named the character Lapinyuu after an intentional Gratuitous Japanese mishearing of "loving you".

Film

 * The Toblerone from Escape 2000.
 * Similarly, in The Santa Clause, the poem "The Night Before Christmas" is read. Upon hearing the line "there arose such a clatter", the boy asks where the "rose suchak ladder" came from. Then when Santa turns out to be real, a ladder made by the Rose Suchak company magically appears as well.
 * Withnail and I: Peter Marwood. The surname comes from the script, the first name comes from the fact many fans have independently and distinctly misheard, "He's just had an audition for rep," as "Peter's just had an audition for rep."

Literature
"Olive: Oh, like in the song? Round John: I don't know what you're talking about."
 * "Olive, the other reindeer."
 * Who later had a children's book written about her which was adapted into a animated special. She was a dog.
 * Other characters in the animated special include Richard Stands (from the U.S. Pledge of Allegiance, "and to the Republic for Richard Stands/which it stands") and Round John Virgin (Silent Night, "round yon virgin, mother and child"):


 * In Bored of the Rings, happy fun explosive toys come in crates labeled with the name of "a fairy whose name was something very much like 'Amy Surplus.'"

Live Action Television

 * Richard Castle, was named deliberately so that when people yelled his nickname, "Rick Castle!", it sounded like "Rick Asshole!". He isn't that bad, really, just a bit dangerously charming. It's Nathan Fillion - the guy is Made of Win.
 * Walter Harriman of the SGC got his last name through a Mondegreen of an actor (perhaps Don S. Davis?) either accidentally calling him "Airman" or yelling "Airman" in his general direction. Previously he was Walter Davis. (His first name was added on a whim by Richard Dean Anderson).
 * In one episode of Star Trek: The Original Series, Spock looked off camera and yelled what sounded like, "Take over here, Ryan!" and then recurring background extra Lieutenant Leslie said, "Yes, sir!" and obliged. Fans decided that the lieutenant was actually a completely different character from Mr. Leslie who just happened to share the same actor, and Lieutenant Ryan even had a Star Trek Wiki page for almost a year. Then one user posted the official subtitle of the scene, and showed Spock was saying "Take over here Rand!" referring to a main character, Janice Rand, who for some reason did not follow Spock's order. It's confusing. But to make a long story short, Lieutenant Ryan never existed.

Music and Folk Rhymes

 * "Howard be thy name". Usually this is just meant in joke.
 * Also seen as "Harold be thy name".
 * The same goes for the hymn lyric "Andy walks with me".
 * The Trope Namer is the same as for Mondegreen.
 * Also, "Gladly the cross-eyed bear."
 * Mentioned in "Hide Away, Folk Family" by They Might Be Giants.

Theatre

 * "Juryman O'Neill" from Trial by Jury ("Kneel, Jurymen, oh, kneel!")

Video Games

 * "Gay Luigi" from Hotel Mario ("Nice of the princess to invite us over for a picnic, eh Luigi?"), by way of YouTube Poop.
 * And "Gay Bowser" from Super Mario 64 ("So long-eh, Bowser!").
 * "Weegee" from the PC version of Mario Is Missing! is a similar case to "Gay Luigi" and has also seen usage on YouTube Poop
 * Ghetsis from Pokémon Black and White is sometimes known as Dennis due to misinterpretation of the background music during his fight.
 * Before the theme was known to belong to Ghetsis, the nickname belonged to Genesect.
 * Halo: Combat Evolved introduced to us "Dustin Echoes", after a line where Cortana responds that all that's left is "just dust and echoes." Bungie even joked about this on their commentary for the cutscenes!

Web Original

 * Sweet Bro and Hella Jeff has a basketball player accidentally named "Hass The Rock", because the dialogue referencing him having the "rock" (ball) mispells "has" with an extra S. His official name is "The Big Man".
 * And similarly in Homestuck, Grandpa Harley became Hass "The Flame" Harley in Fanon.

Western Animation

 * In Beast Wars, Cheetor winds up in the ship the Predacons use as their base and is told by a melodramatic Terrorsaur "Welcome to The Dark Side." And that is how the ship became known as the Darksyde (the "y" was added later to dodge copyright issues).
 * A sea serpent in My Little Pony Friendship Is Magic was given the Fan Nickname "Steven Magnet" after YouTube's automatic audio transcription gave that as the transcription for one of his lines.
 * The Venture Brothers: "Dawn Venture" is an in-universe example; thanks to a misunderstanding associated with a cross-dressing Dean's marriage to Baron Underbheit at sunup, Hank is convinced to this day that he has a long-lost sister named Dawn.
 * Thief King Bakura of Yu-Gi-Oh!! is sometimes fanonically referred to as Afekia, due to a mishearing of 'a thief'.
 * When this tropper was little she thought that Littlefoot in The Land Before Time was called "lamby" from hearing the title as "Lamby For Time."

Real Life

 * A theory on the origin of the bloody term "bloody" is that it was originally "by Our Lady" (the Virgin Mary) and was misheard and corrupted over multiple bloody generations to this bloody term.