Season 21, multiple episodes.

"I have an idea! How about casting one token unstable person per season as quick occasional distractors from non-stop, tiresome chatter about idol paranoia and S P L I T T I N G V O T E S."

In this entry, a P.E. teacher is threatened by another woman's willpower and refusal to turn into a vegetable after losing her leg, so she does what anyone would do -- taking her insecurity out on the woman's prosthetic leg visa vie hateful interviews and even physically assaulting her with barely any reason.