10.During Season 9 of Criminal Minds, Shemar Moore (Derek Morgan) shaved his goatee, messing up the continuity of the scenes they were filming. Naturally, the cast and crew got him back for it.
Here's the full behind-the-scenes look at the joke:
11.During an interview with TV Guide Magazine, Misha Collins (Castiel) described Jensen Ackles (Dean) and Jared Padalecki (Sam) treating him like "a pledge at a fraternity that has a really heavy hazing ritual" throughout his early days on the show. He also retold the story of the worst prank they pulled on him in (at that time) 14 seasons.
12.This one didn't happen on set, but it was technically between two co-stars: Kit Harrington (Jon Snow) and Rose Leslie (Ygritte), of Game of Thrones fame. Harrington pulled off an April Fools' joke that was so grisly, it threatened his marriage.
Here's The Jonathan Ross Show interview where Harrington tells the story:
13.During the climatic trial sequence from Season 4 of Game of Thrones, Nikolaj Coster-Waldau (Jaime) and Peter Dinklage (Tyrion) broke the tension by entering the scene singing and dancing...though they may have ended up making it even tenser than before.
Here's Coster-Waldau telling the story for The Tonight Show Starring Jimmy Fallon:
And here's the footage of the moment itself:
14.Emilia Clarke (Daenerys Targaryen) got in on the GOT fun by drawing on sleeping co-star Joseph Naufahu (Khal Moro) with caramel.
Here's the clip:
15.In a scene from the 2013 comedy We're the Millers, TLC's "Waterfalls" was supposed to play, but Jason Sudeikis and the rest of the cast changed it to the Friends theme song to surprise/annoy Jennifer Aniston.
Here's a clip, which made it onto the movie's blooper reel:
16.Finally, while filming Star Trek Into Darkness, Benedict Cumberbatch (and other members of the cast) were tricked into wearing "neutron cream" to protect their...neutrons while filming scenes in a scientific facility.
Here's a behind-the-scenes look at the practical joke:
Do you have a favorite story about an on-set prank? Tell us about it in the comments!