The Northern Lights Rooftop Party was introduced in the episode, "Power Animal." This was the episode's first scene where Finn and Jake climb up to their rooftop for the party. When they're at the top, Finn does a backflip to amuse his guests and Cinnamon Bun compliments him by saying he always focuses. Jake asks Cinnamon Bun if he focuses, Cinnamon Bun replies, "Jake, you don't focus at all." But Jake wasn't listening because he was trying to toast the Ice Cream.
It was then, a hefty gnome, approached Finn. He asked Jake who the gnome was as he refers to him as "super weird," and Jake replies that he thought the gnome was his friend. It was then they're attention was caught when Princess Bubblegum announces that the Celestial Alignments (auroras) are starting.