- Vincent Martella (Phineas Flynn (voice))
- David Errigo Jr. (Ferb Fletcher (voice))
- Ashley French (Candace Flynn (voice))
- Caroline Rhea (Linda Flynn-Fletcher (voice))
- Dee Bradley Baker (Perry the Platypus (voice))
- Alyson Stoner (Isabella Garcia-Shapiro (voice))
- Dan Povenmire (Heinz Doofenshmirtz (voice))
- Jeff 'Swampy' Marsh (Francis Monogram (voice))
Phineas and Ferb — S3E9
Episode: Misperceived Monotreme
Air Date: 2011-05-13
Runtime: 11 min
Overview
Perry misses his 100th battle against Dr. Doofenshmirtz when Candace takes him to the Charity Pet Wash with her. Perry's absence goes unnoticed when the zookeeper's typical platypus at the Danville Zoo stops Dr. Doofenshmirtz's plan to zap his brother with his "Least Likely-inator." Meanwhile, the boys build a fun house Phineas and Ferb style.