S04E18: La Candace-Cabra

The boys set out to prove the existence of the elusive Chupacabra to the world, but Candace can't stand the wait and needs to first just prove it to Mom. Meanwhile, Doofenshmirtz has the brilliant idea to use his Switch-Place-Inator to remove hair from one person and give it to another so that he can in turn sell his hair growing tonic.