Boney first appears in "Vault of Bones" when Finn and Flame Princess are exploring a dungeon while he was fishing. Flame Princess wanted to burn him alive, but Finn said that that would be "a little cruel, even for an evil guy." Finn then demonstrated to Flame Princess how to "shake them down" to get loot from him. Finn made the skeleton do the splits and give him a map. The skeleton does not like it when Finn yells.
Boney is relatively big, has a large skull, and was seen using his loose right arm as a fishing pole.