(Although you may have seen it on DeviantArt:)
In this short fan-animated Adventure Time episode, Fionna and Marshall Lee are turned into ghosts, but can they break the curse before they’re stuck that way forever?

Title card — Gabriela Granado
Voices, music — Gene Cochrane
Voices, writing — Boggy
Animation, storyboard, voices — Lydia Fama (Me!)

This is the deviant art link if you want to watch it with the maximum quality!! (and say THANKS!)