Minor Character, Major Song

A minor character in a musical or opera, who only gets one song, but that one song is really, really memorable. When the musical is discussed, he's the one who makes people say, "And what about that one guy who sang..." Sometimes this is a result of Adaptation Distillation that removes the character's part from other songs (or removes the other songs entirely).

Compare One-Scene Wonder.

Film

 * Ron Holgate as Richard Henry Lee in 1776, who carries some great big wonderful slabs of roast pork while he's singing "The Lees of Old Virginia."
 * Eddie the (Ex-)Delivery Boy from The Rocky Horror Picture Show. He shows up, sings one of the most memorable songs in the movie, and is promptly murdered with a pickaxe. He has one later song (titled "Eddie", in fact), but this verse is a voiceover intended to represent other characters reading a letter he wrote.
 * Harold the Juicyfruit/Undead leads the most instantly memorable song (and scene) in Phantom of the Paradise ("Somebody Super Like You"), but elsewhere in the film he's only seen a handful of times and isn't even recognizable without his heavy goth makeup.
 * Amos Hart, singing "Mr. Cellophane" from Chicago. John C. Reilly's performance of this one song earned him a Best Supporting Actor nomination.
 * Likewise, Queen Latifah's one song ("When You're Good to Mama") in the same film. Her character was bigger than Reilly's, however.
 * Elton John's "Pinball Wizard" and Tina Turner's "Acid Queen" from Tommy.
 * The Don in the "Il Muto" scene in The Phantom of the Opera.
 * Julie Brown in Earth Girls Are Easy with "Cause I'm a Blonde".
 * The dentist in Little Shop of Horrors. Could be considered a subversion, as in the stage musical it was adapted from, the dentist actually sung in two other songs (the same ACTOR also sung in a multitude of other songs, And You Were There-style).
 * Vendice Partners in Absolute Beginners. He's just one of several antagonists in on an evil scheme, but since he's played by David Bowie he gets the Bowie-penned song "That's Motivation" and a Disney Acid Sequence to go with it. Between that, writing/singing the Title Theme Tune for the film's credits, and simply being the biggest name in the cast, Bowie was billed third! (As a bonus, while his character only sings a snatch of the old standard "Volare" in one scene, the soundtrack album includes a full performance of it.)
 * King Gator, who does the so-called Big Lipped Alligator Moment in All Dogs Go to Heaven.
 * In The Rundown Ewen Bremen got his own major song that began the film's Crowning Moment of Awesome when he was playing his bagpipes towards the end.
 * Afterglow from Bran Nue Dae, sung by the resident hippy of the film, Annie.
 * Phantom of the Paradise: The Juicy Fruits/ Beach Bums/ Undeads are rarely on screen, and only one of them has a speaking part, but they sing three of the major songs, "Goodbye, Eddie. Goodbye", "Upholstery" and "Somebody Super Like You", which was released as a single.
 * The guy in Singin' in the Rain who sings "Beautiful Girls" isn't even credited.
 * His name is Jimmy Thompson, by the way.
 * In the same movie, Cyd Charise is a minor character with a major dance number.

Live Action TV
""They got... the mustard... out!""
 * David Fury as "The Mustard Man" in the Buffy the Vampire Slayer Musical Episode, "Once More With Feeling".


 * Another "Once More, With Feeling" example would be Sweet, the demon summoned that causes everyone to burst into song and then occasionally into flame. He only has one song ("What You Feel") and a tiny reprise, but he drives the action, and it is - "a showstopping number". But then, he's played by Broadway legend Hinton Battle.

Theater

 * "Miss Marmelstein" from I Can Get It For You Wholesale. This minor piece helped kickstart the career of Barbra Streisand.
 * King Herod ("King Herod's Song") and Simon ("Simon Zealotes") from Jesus Christ Superstar.
 * The Foreign Woman, from Gian-Carlo Menotti's The Consul. To be fair, she is onstage for more than the one aria she sings, but that aria is her only real point of significance.
 * The Steersman from Wagner's "The Flying Dutchman" might qualify.
 * Nimue, from Camelot, who sings "Follow Me."
 * Steve, from Paint Your Wagon, who sings "They Call The Wind Maria."
 * The Young Confederate Soldier from Parade.
 * The girl who sings "Somewhere" in West Side Story.
 * Gigi from Miss Saigon.
 * The Street Singer from The Threepenny Opera, who sings "Mack the Knife."
 * The Proprietor from Assassins. He sings "Everybody's Got the Right" at the beginning of the show. Though he does show up at various points, as a background character, an announcer, or even the President of the United States. And in some productions, he does sing part of "Another National Anthem."
 * Parpignol from La Boheme, who sings about two lines.
 * The lover from Evita, who sings "Another Suitcase in Another Hall" and is quickly dismissed. In the film version, Evita herself sings it because, y'know... Madonna.
 * Pirelli in Sweeney Todd: The Demon Barber of Fleet Street.
 * Kiss Me Kate: Those Two Bad Guys who sing "Brush Up Your Shakespeare."
 * Catch Me If You Can: "Fly, Fly Away", sung by Brenda Strong, Frank Abagnale Jr's love interest. The fact that this is just a major song is the understatement of the year, because this song is pretty much the hit of the show.
 * Joe in Show Boat. It helps that he has one of the best Broadway songs ever written, "Ol' Man River."
 * The Piragua guy in In the Heights.
 * Arguably, Petra of A Little Night Music with "The Miller's Son." She does have a relatively small part in the "A Weekend In The Country" musical sequence, but she is the only non-central character to get a song all to herself which ends up having little to no bearing on the plot.
 * Nicely-Nicely Johnson in Guys and Dolls, who gets one of the greatest Eleven O'Clock Numbers in theatre - "Sit Down, You're Rocking the Boat".
 * Martha from Spring Awakening is a minor character whose only major song is "The Dark I Know Well," a duet with Ilse about their physically  Abusive Parents. The actresses frequently get thanked by fans who were also abuse victims.
 * Pan in Bat Boy the Musical qualifies with "Children Children". He shows up randomly and sings a song that is memorable for not fitting in with any of the rest of the show; particularly due to a bunch of animals that proceed to have an 'interspecies orgy' during said song. He is also never named.

Music

 * The War of The Worlds gives the epic duet "The Spirit Of Man" to the minor but hammy Parson Nathaniel and his even more minor wife Beth.