Rimpler

Rimpler (polish: Gnieciuch), a rat-like monsters, were supossed to appear in base game during its development in 2013 - 2014 but they were removed at some point of development and we would not know of all of this if not of leaked materials. In slavic mithology its creature that is choking humans during sleep.

Informations from leaked materials
Creature resembling hybrid of a cat with a rat. During the night, Gnieciuch sits on a drunk's chest and suffocate him, sometimes to death. The creature is very fast and agile, that’s why nobody’s, even with a great reflex, can catch it.

Defence

 * Dies after single hit.
 * Doesn’t fight - tries to run away.