Wilhelm scream

The Wilhelm scream is a scream sound effect which was introduced in the 1951 film, Distant Drums. It is used as an in-joke as it appeared in many animated films, most notably from Disney and DreamWorks Animations, comedy films, action films, and all Star Wars films. It has appeared in many Pixar films and is most recently used in Monsters University. The running gag is similar to other Pixar running gags, A113 and the Pizza Planet truck.

Pixar films that use the Wilhelm scream

 * Toy Story (1995) - When Buzz Lightyear gets pushed out the window by a lamp.
 * Cars (2006) - When a car gets zapped by a laser during Lightning McQueen's daydream of being sponsored by Dinoco.
 * Your Friend the Rat (2007) - When an astronaut got frightened by another rat.
 * Lifted (2007) - When Ernie falls off the crater at the very end credits.
 * Up (2009) - When the dogs are falling off a cliff while attempting to chase Carl Fredricksen and Russell with the bird, a Wilhelm scream can be heard.
 * George and A.J. (2009) - When one of the houses burrows down, the Wilhelm scream can be heard.
 * Day & Night (2010) - During the movie scene when the cowboy shoots a man offscreen.
 * Toy Story 3 (2010) - During the opening scene, while Andy and his toys are watching a "scary movie" during the "You've Got a Friend in Me" sequence, a Wilhelm scream can be heard.
 * Cars 2 (2011) - When the cars in the Ye Left Turn Inn beat Grem and Acer up.
 * The Legend of Mor'du (2012) - When Mor'du throws down soldiers from a rock, the Wilhelm scream can be heard.
 * Monsters University (2013) - When Mike unknowingly runs over a student with the floor waxer.