The Ny'ghan Grii are a fictional race created in 1994 by Chaosium for the Call of Cthulhu RPG, based on Henry Kuttner's the Invaders.
Background
The Ny'ghan Grii are an extra-dimensional race of luminous spherical creatures that moves by crawling or floating, accompanied by icy cold and a thick fog. They seek entry to other worlds, searching for sacrifices or disturbances in the time/space fabric that will give them entry. Beings which attack with a chilling blast and their tentacles, and have the ability to devolve victims into increasingly bestial forms.