Revealing mistake: When Leela brings soup to Zap and Amy in bed. Leela is wrapped up by a tentacle. The animator forgot to erase the lines of the tentacle as it overlaps. A huge graphical error can be seen.
Futurama: The Beast with a Billion Backs (2008)
1 revealing mistake - chronological order
Directed by: Peter Avanzino
Starring: John DiMaggio, Katey Sagal, Tress MacNeille, Billy West
Continuity mistake: During the Deathball Match, the booth window is smashed and Wernstrom gets knocked onto the court, however in the next overview shot, the window is intact and he is still standing behind it. (00:15:10)
Trivia: After Bender makes a point with the organic eye, there's a picture of Robot B-9 from the Lost in Space TV series on the wall.