- Previous episode S12E05 - The Planetarium Collision
- Number S12E06
- Director Mark Cendrowski
- Writers Steve Holland, Maria Ferrari, Tara Hernandez, Eric Kaplan, Jeremy Howe, Adam Faberman
The Imitation Perturbation
When Wolowitz dresses up as Sheldon for Halloween, Sheldon seeks retaliation at Leonard and Penny’s Halloween party. Also, Leonard is shocked that Penny doesn’t remember their first kiss.