Jump The Shark
Jumping the shark is an idiom created by Jon Hein that was used to describe the moment in the evolution of a television show when it begins a decline in quality, signaled by a particular scene, episode, or aspect of a show in which the writers use some type of "gimmick" in an attempt to keep viewers' interest, and which is taken as a sign of desperation. The phrase is based on a scene from a fifth-season episode of the sitcom Happy Days when the character Fonzie jumps over a shark while on water-skis