The Eyes: [s2e2]

It is revealed that the Ice King is inside the horse costume, spying on Finn and Jake to learn their "secrets to being happy". Viewing Context

Generally considered filler . While it doesn't advance the main lore, it is often cited by fans as one of the funniest episodes of the early seasons. [S2E2] The Eyes

You can find this episode on streaming platforms like or for purchase on the Apple TV Store and Amazon Prime Video. List of important adventure time episodes - GitHub Gist It is revealed that the Ice King is

Finn and Jake are exhausted and just want to sleep, but a strange, googly-eyed horse is staring at them from outside the Tree Fort. Their increasingly desperate attempts to get rid of the horse (including playing a lullaby and disguising themselves) fail until they discover it’s actually a costume. You can find this episode on streaming platforms

"It Came from the Nightosphere" (S2E1) — A major lore episode introducing Marceline’s father.

"Loyalty to the King" (S2E3) — A highly recommended episode for Ice King's character development. Where to Watch