Kilmulis

A kilmulis is a hunched, neckless, simian humanoid with a really tough skull.

The Lady of the Lake
One of them was encountered by Geralt in the basement of the Pomerol estate in Toussaint, along with a korred, a pryskirnik and a creature which resembled first a candelabra, and later a Yule tree with glowing eyes and which didn't feature in any witcher tomes.