The Sitters.

A pet sitter comes to watch a cat for the first time. He finds a list of cat-sitting duties in a puddle on the counter next to a spilt glass of water. The writing on the list has blurred and is illegible. As he begins to do the tasks, The Cat follows him around leaving inky black trails. The Cat scratches him, licking the blood from his claw. Nervous and hurt, The Sitter goes to clean the litter box where he finds a bone buried. He looks up what kind of bone it is, discovering it is a human tibia.The Cat then transforms into a terrifying monster, throwing The Sitter from the couch and the phone from his hand where it hits the ground and accidentally calls The Owner. The Owner, now on speaker, say they cannot help. The Cat bites off The Sitter's hand and after a cat-and-man chase scene, The Cat swallows down The Sitter and returns to his normal cat shape.