"Loyalty to the King" (S2E3) — A highly recommended episode for Ice King's character development. Where to Watch
"It Came from the Nightosphere" (S2E1) — A major lore episode introducing Marceline’s father. [S2E2] The Eyes
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. "Loyalty to the King" (S2E3) — A highly
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 Their increasingly desperate attempts to get rid of
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.