Pumpkaboo resemble Jack-o-lanterns with only two round holes as eyes and no other features. On top of that is the Pokémon's real head, resembling a brown bat. They also have a pair of stubby feet on their pumpkin-body.
Pumkaboo come in four different variations: Small Size, Average Size, Large Size, and Super Size. The call of the Super Size version is deeper. Only Average and Super Size Pumpkaboo can have the Hidden Ability "Insomnia" which prevents them from falling asleep.
Shiny Pumpkaboo have a purple pumpkin-body and a black head.
Pumpkaboo's pumpkin bodies are inhabited by a spirit who is trapped in our world.
These Pokémon are active during the night. With their glowing eyes, Pumpkaboo light the way for travelers. They also carry lost souls to the place where they belong so they can move on.
During the day, Pumkaboo sleep on the ground.
In the Anime
The character Jessie has a Pumpkaboo. During the episode Pokémon XY: Kalos Quest: A Festival Trade! A Festival Farewell?, it evolves into a Gourgeist after being traded.