|What Was Missing|
|Season 3, Episode 10|
|Air date||September 11, 2011|
|Written by||Adam Muto and Rebecca Sugar|
|Directed by||Larry Leichliter|
"Fionna and Cake"
What Was Missing is the 10th episode of Season 3 of Adventure Time. It first aired September 26, 2011.
- This is the episode that started the whole band.
- The title of the episode has a confusing meaning, because it could mean that something was missing in the songs that they were singing, or the fact that the Door Lord was stealing everything, and making those things missing.
- This episode reveals that Princess Bubblegum and Marceline have a "friendly rivalry".