The Imitation Perturbation is the sixth episode of the twelfth season of The Big Bang Theory.
While having dinner at the Hofstadter’s apartment, Raj mentions that it’s the fortieth anniversary of the movie "Halloween", though Sheldon doesn’t really understand what he’s talking about, and goes over the origins of the holiday. Amy asks if anyone is going to dress up at work. Bernadette tells them about the time someone dressed up as a zombie, causing a quarantine. Leonard proposes that they have a Halloween party.
- The episode was released on the 40th anniversary of John Carpenter's Halloween.