is the second episode of Season 2 of Adventure Time . In this episode, Finn and Jake try to get some sleep but are haunted by a bug-eyed, staring horse outside their window, which eventually leads to a confrontation with the Ice King. Quick Episode Guide
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.
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
"It Came from the Nightosphere" (S2E1) — A major lore episode introducing Marceline’s father.
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.
If you are following a specific watch order, here is how it fits: