 Although his appearance as a domestic pet is mostly a cover , Perry has nonetheless expressed care and devotion for the Flynn @-@ Fletcher family . In the episode " The Ballad of Bad <unk> " , Perry managed to drag Candace out of the Dark Cave before it <unk> in because of Dr. <unk> 's " self destruction button " that which Candace had accidentally pressed while under the orange moss <unk> , thinking it was a <unk> machine . He did this even though he knew that Candace saw that Perry was a secret agent talking to Agent E ( Eagle ) and to Major Monogram in a cracked egg . Candace thought she was just <unk> because of the orange moss she accidentally touched earlier in the episode . Also , when an invention of Doofenshmirtz 's in the episode " Journey to the Center of Candace " might cause severe harm to Phineas and Ferb , Perry thoroughly beats up Doofenshmirtz and quickly handcuffs him . He then ties him to a pipe and , instead of just leaving him like he usually does in the series , calls for special forces from the O.W.C.A. to come and arrest the doctor , though they never show up . In " Oh , There You Are , Perry , " Doofenshmirtz is downgraded to a low threat level and Perry is reassigned to a new nemesis . This causes him to have to leave his home with the Flynn @-@ <unk> , which makes him sad and he does not enjoy his new villain . Phineas and Ferb are fearful about where Perry could have gone to and put up several <unk> around town for people to find him . They decide to throw a concert on the roof of a building , singing a song about how much they love Perry and want him to come home . <unk> , Perry is reassigned to Doofenshmirtz again and returns to the brothers once more . 
