S04E27: Face Your Fear

After studying hours of horror movies, Doofenshmirtz develops a theory that enlarging small, cute animals into giant beasts will help him take over the Tri-State area. But when he puts his plan into action, he soon realizes it might be too much for him to handle. Meanwhile, Phineas and Ferb make a giant revolving foam city so they can safely perform skateboarding tricks, and Candace's tour of the Danville Space Laboratory gives her an opportunity for a high-tech bust.