The Merks are an alien species featured in the Ghostbusters RPG's Hot Rods of the Gods.
"Ugly, hulking gray-brown alien toughs. Where the Fuggs are vibrant, energetic, and imaginative, the Merks are dull, lazy, and uninspired. They enjoy mindless violence, as opposed to the creative partying of the Fuggs.
Like the Fuggs, the Merks re-grow after death."