Ep 26. Not Phineas and Ferb / Phineas and Ferb-Busters!

In the episode Not Phineas and Ferb, the boys accidentally switch bodies with Perry the Platypus after Dr. Doofenshmirtz's latest invention malfunctions. The boys have to navigate their lives as a platypus while Perry jumps into their human world. Meanwhile, Candace tries to bust the real Phineas and Ferb for creating a giant spaceship, but keeps encountering Perry in their place.

In the second half of the episode, Phineas and Ferb become obsessed with finding the mysterious "Phineas and Ferb-Busters," a duo of kids who have been debunking their inventions all over town. Perry helps them track down the culprits but the boys are surprised to discover that the Phineas and Ferb-Busters are actually their own friends, Baljeet and Buford, who have been jealous of their success.

The episode features plenty of zany humor and imaginative inventions, as well as a fun twist on body-swapping tropes. Fans of the show will enjoy the subplot about the Phineas and Ferb-Busters, which provides an interesting insight into the boys' relationships with their peers and how their outlandish projects affect the people around them.

Overall, Not Phineas and Ferb / Phineas and Ferb-Busters! is a hilarious and creative episode that showcases the best of what the show has to offer. It's perfect for fans of all ages and is sure to leave everyone laughing and entertained.