"On Old MacDonald's Special Song" is an episode of Special Agent Oso.
Oso is given a training mission from Professor Buffo to open a garage by pressing buttons on a keypad in a certain pattern. Oso presses all the buttons at once and gets launched into the air. He gets a special alert. A boy named Henry is having trouble playing "Old MacDonald" on the piano while his grandpa is taking a nap. So Oso decides to teach Henry how to play the song properly before his Aunt Stephanie comes over so he can play for her.
- The episode's title is a reference to the James Bond film On Her Majesty's Secret Service.