Phineas and Ferb (2007)

S02E23 No More Bunny Business

Candace discovers a rabbit and immediately wishes to keep him as a pet, unaware that he's actually a rogue agent on a mission to locate Perry's secret lair for intel. Meanwhile, Phineas and Ferb embark on a project to create x-ray glasses. With Perry absent to thwart his schemes, Doofenshmirtz encounters an unexpected new adversary in his latest plan.