Der Kinderlumper Phineas and Ferb : Season 4 Episode 6

The boys create Rutabaga-themed vehicles when Candace is chosen to be Rutabaga princess and gets to start the "Running of the Chinchillas." Across town, Doofenshmirtz plans to turn himself into a real live Kinderlumper to scare Roger into relinquishing control of the Tri-State Area over to him.