Recap: Phineas And Ferb The Monster Of Phineas N Ferbenstein
It's a rainy day, and Phineas and Ferb's plans have been cancelled, as well as the power. So to pass the time, Ferb's grandpa Reginald recalls the tale of one of his ancestor's creating a platypus monster.
Meanwhile, the power is out in Doofenshmirtz's building as well, and Dr. D has ended up locked inside. When Perry comes and locks himself in too, Doofenshmirtz tells him the story of one of his ancestors, who created a concoction that would turn him into a monster.