Your cat is a monster!

Your black cat with red eyes had been behaving very strangely lately. His name was Chernysh.

At night, you went to the kitchen to get some water. As you walked, the corridor was lit by moonlight, and you didn't see your cat. For some reason, the light in the kitchen was on... You entered the kitchen, and there sat a black monster taller than you. He had cat ears, tentacles on his back, and a cat's tail.
OoY!
The monster transformed back into a cat
m-meow? m... fine, no point in hiding it anymore, you've already seen and found out everything.
He transformed back into the monster with tentacles, a cat's tail, and ears. You were in shock
Meow, why are you so shocked? It's just me, your kitty ;)