Traveling Pipe Bulge

Mostly found in animated and CG media, the Traveling Pipe Bulge is a phenomenon that occurs when an object moves through a pipe or hard tube, creating a bulge to tell you where it is. Bonus points if the fittings do not contract after the object passes through them.

Sister Trope to Worm Sign, Dinner Deformation and Balloon Belly.

Eastern European Animation

 * In one episode of Staflik a Spagetka, it was done inside a monocular.

Film -- Animated

 * Happens in The Nightmare Before Christmas when objects (such as Santa Claus) go down the pipe to Oogie Boogie's lair.
 * In a rare variance of this trope, Santa's transport causes bolts to pop out of the pipe.
 * In Horton Hears a Who (the Jim Carrey version), this happens when Horton's voice first travels down the pipe to the mayor's office.
 * The Thief does this extensively while trying to sneak into the castle in The Thief and The Cobbler.

Film -- Live Action

 * Happens in Deep Rising when the worm monsters pass through pipes.

Live Action TV

 * They did this in the Red Dwarf episode "Polymorph".
 * Mighty Morphin Power Rangers: Rita's Monster-Matic (a magic kiln that turns clay figures into full-sized beings, either monsters or Putty Patrollers) displays this with its exit pipe.

Video Games

 * Several recent Super Mario Bros games have this (but not the NES or SNES games).
 * Super Mario World 2 Yoshis Island had this.
 * Happens in Tales of Monkey Island, Chapter 3. Although in this case it's a bile tube, not a pipe.
 * Many tubes in Loco Roco are very flexible, allowing to stretch so a locoroco could traverse pipes and other things in one piece.
 * In the DS version of Sonic Colors, there are a few elevators in Tropical Resort which bulge when Sonic enters them.
 * In Generation 1-3 Pokémon Cable Link trades.
 * When Kirby goes behind the background in Kirbys Epic Yarn, it bulges, as do cannons when he's inside them.
 * Spellbound Dizzy has a few pipes that lead to new areas. One of these is actually a man-eating flower.
 * In The Bugs Bunny Crazy Castle, these show up whenever Bugs enters a pipe.

Western Animation

 * Happens in the Darkwing Duck episode "Dry Hard", when The Liquidator is passing through the pipes of the city waterworks. ("Followwwww that piiiiipe!")
 * Fanboy and Chum Chum has their straws showing bulge of Frosty Freezy Freeze as they suck it from the source.
 * In the 1935 Looney Tunes short "Billboard Frolics", a cat traps a dog in a piece of pipe, which bulges where the dog thrashes around inside.
 * In one of Chuck Jones' Tom and Jerry cartoons, Jerry escapes into a gutter; when Tom follows, there's a noticeable bulge.
 * Also, any time Jerry (or tar/air/etc) goes through a garden hose.
 * Felix the Cat: "Felix Doubles for Darwin" short has a whole scene of Felix traveling through the entire transatlantic cable and then back again, pursued by apes.
 * Mario & Luigi in the Super Mario Bros Super Show.