I effing hate the term "Jump The Shark." It's last acceptable use was when Henry Winkler actually bunny hopped over a dead one on Arrested Development. I have used, and prefer to use the term "Rossed" or "Rossed Up" tp refer to the sudden change of a character, plotline, o situation that went from normal/plausible to effing stupid. The Genesis of this, is of course, Ross Geller, who during his tenure on Friends, went from nervous nerd, but with semi-redeeming qualities, to complete miscreant and otherwise dirtbag of society.

More recent examples of "Rossing" include

• Most of the second series and the first 2/3 of the third series of Lost
• Pirates of the Carribean 3
• Spiderman 3
  

Explanation: "Rossed" or "Rossed Up"