Phineas And Ferb - Season 4 - the fourth and final season of Phineas and Ferb first aired on Disney Channel. An animated comedy about two stepbrothers who find inventive things to do on each day of their summer vacation such as building a roller coaster out of materials you would find in your everyday home like Popsicle sticks, indoor plumbing, etc. Unbeknownst to them, their pet platypus, Perry, leads a double life as a secret agent.