How does Fifi know Leonoard's clown act isn't funny? She's never seen it.
Leonard says he's 10 years old, but he didn't turn 10 until Party Animal.
Leonard's hair changes back and forth between orange and blue.
When Mrs. Helperman is about to announce the winner, Scott is standing in front of the class next to Ian and Leonard. When she finally announces the winner and the entire class cheers, Scott can be seen sitting at his desk cheering along with the rest of the class. Afterwards he's back at the front of the class standing next to Leonard.
Spot gets opposable thumbs when he's Scott.
Where did Spot get his glasses?