Colloquial Terms: The Rake, Whisperer, Pawmark, Ravage, FERAL, Fermata
Physical Characteristics: Humanoid creature that moves on all fours. Claws protrude from fingers which are often described as "knife-like". Smaller claws are sometimes observed protruding from toes. Skin is pale and hairless. Lacks both sexual organs and an anus. Teeth are all pointed. Eyes are larges, round, and black.
Behavioral Characteristics: Often is observed entering into the rooms of sleeping victims and whispering words to them. Will often turn violent if victims awaken. Is sometimes observed hunting for meat, usually targeting humans.
Further Reading: This account has made the rounds on the internet a fair bit. It's often believed to be a fictitious "creepypasta", but the woman and her story are very real (or they were. She's dead now). The blogs The Hunter, Moonlit Whispers, and Perchance to Dream also concern this creature.