A character crushed by an Anvil on Head or other large object (e.g. piano) will often stumble away, being squashed into a pleated and flexing shape like an accordion, frequently accompanied by accordion music.
And no, it's not a new and bizarre Robot Master.
- Chester Cheetah of Cheetos fame got that way from falling into a sewer.
- Wario, when he gets slammed by a massive hammer, turns into one of these; it gives him super bouncing powers.
- Space Quest, in the falling death pictures in the third and fifth episodes.
- In Rayman Origins, Globox can flatten himself into an accordion shape when ducking.
- One of Bubsy's death animations is this.
- In Super Mario World, Rex becomes this after Mario stomps on him once.
- In Sid And Als Incredible Toons, an Anvil on Head will accordionize Sid, with the usual sound effect.
- Happens to Monterey Jack in the third part of the Chip 'n Dale Rescue Rangers Five-Episode Pilot "To the Rescue". When Fat Cat accidentally steps on him while running, he turns into an Accordion Mouse for a second before stumbling on along his way.
- Happens to Peter in Family Guy when, true to form, a piano falls on him.
- The Mickey Mouse cartoon The Cactus Kid (happens to Pegleg Pete) and others.
- Frequented a lot of Tex Avery cartoons.
- Several Tom and Jerry cartoons have this trope, such as "Neapolitan Mouse", in which the Italian dog that gave Tom that injury promptly proceeded to play Tom like an actual accordion.
- And plenty of Looney Tunes shorts. A certain Coyote, Wile E., is occasionally subject to this, with appropriate sounds. On a couple of occasions, a crashing piano gives him piano keys for teeth which began spontaneously playing a song, instead of turning his body into an accordion.
- Oggy and the Cockroaches: It's accordion cat, not accordion man.
- It happened a couple of times in Rocko's Modern Life, most notably after Rocko and Heffer crash into the ground on a cheaply made roller coaster (as pictured above).
- It happened to Eddy in the Ed, Edd n Eddy episode "Tag, Yer Ed", after Lee Kanker slammed him head first into a wrestling mat. She then starts playing him like an actual accordion.
- Edd suffers a similar gag in "Laugh, Ed, Laugh", getting smacked into a street lamp while trying to subdue a scam-deprived Eddy. When Ed picks him up off the ground, he's scrunched flat and has a hilarious dazed look on his face.
- An episode of KaBlam! had Henry and June bring in the guy who invented it, but then his thank-you list was too long, so June sent down an anvil on him...and he performed the trope.
- Happens to Lucius on Jimmy Two-Shoes.
- Ned's Newt, episode "New Improved Zippo": One of the forms Newton can't control is that of an accordion.
- The Jungle Book featured a variation of this: Whenever Kaa gets his tail caught in some bamboo, when he frees it his tail flies back at him, causing himself to recoil instantly (he is a snake), making an accordion noise as he does so.
- In the Spongebob Squarepants episode "Naughty Nautical Neighbors," Patrick angrily slams his rock house closed, hitting his head in the progress. All to Squidward's joy and complete with accordion sound effects.
- Happens to the giant cat's arm when he tries to punch Mighty Mouse in "The Cat's Tale."
- Happens to Geese Ausbie's wrist in the Harlem Globetrotters episode "The Great Geese Goof-Up" after he misuses the bus jack.
- The teaser to the Garbage Pail Kids Cartoon episode "Heartless Hal" has a man playing Simon Says with the audience and smugly telling unseen participants that they're out whenever he didn't say "Simon Says" or when they do something he didn't say they could do. He eventually gets his comeuppance when he says "Stomp your feet" and gets stepped on by a giant, resulting in the man groaning "I didn't say Simon Says" after he's turned into a living accordion.