Kirby Mass Attack sprites
|“||The haunted mansion that's shrouded in darkness is the perfect home for the Gruegloom. Grueglooms cluster together and try to consume you. So when they surround you, stay in the light!”|
|— Daroach • Kirby Mass Attack|
Grueglooms are actually skulls that are disguised as dark, purple clouds with scary, somewhat odd-looking eyes and a big mouth with fangs.
Grueglooms appear in mostly dark areas. As shown in an in-game cutscene, they enjoy eating small creatures such as Beanbons and will come after any Kirbys they spot. If one happens to get close enough, it will devour the Kirby, instantly KO'ing him. Once eaten, a Kirby cannot be brought back. However, if Grueglooms have light shined on them, they will turn into their true form as vulnerable white skulls. When in this form they can be defeated and taken down easily.
There are also blue Grueglooms that can't be defeated, but disappear when exposed to light.
- Gruegloom's skull-like form resembles Skuller from Kirby's Dream Land.
- Gruegloom is likely based on the grue, a monster from the Zork series of computer games. Like the Gruegloom, grues inhabit dark environments, can instantly defeat the player by eating them and are weak to light. As with the different types of Grueglooms, the effects of light on grues can vary from game to game, either causing them intense pain or making them spontaneously combust.