For those not in the know, Phineas and Ferb is a Disney Channel cartoon about two brothers who devise inventive ways to spend their summer vacation.
Their pet platypus, Perry, is secretly a master spy who fights evil.
While these two separate storylines are going on, sometimes one of the brothers will comment, "Hey, where's Perry?" to facilitate the transition between them. XD
...IT SEEMED LIKE A GOOD IDEA AT THE TIME, 'KAY.
I wanted Ferb!Sam to wear his purple dog shirt in this, but he was already in purple pants, so I just put him in plaid. Perry!Cas should probably be in a trenchcoat but let's face it--how do you dress a platypus?