Episode Titles: Perturbation
You are viewing a list of 1 The Big Bang Theory episode featuring "Perturbation" in their title.
The Imitation Perturbation
Season 12, Episode 6 - Aired October 25, 2018
Sheldon is offended when Howard dresses up like him for Halloween, so he and Amy get their revenge at Leonard and Penny's Halloween party. Meanwhile, Leonard is surprised that Penny doesn't remember their first kiss.