Phineas and Ferb Season 3 Episode 22 - That's the Spirit! Episode Title: That's the Spirit! Episode Description: It's Halloween night and the kids encounter a boy named Russell who is convinced his house is haunted. Meanwhile, Dr. Doofenshmirtz's disdain for grass causes him to invent a "Mind-Transfer-Inator" enabling him to merge minds with a cow and destroy all the grass in the Tri-State Area. Unfortunately, his plan backfires and he transforms into a scary "were-cow" that wreaks havoc any time there is a full moon. It's now up to Agent P to stop him and save Danville.