Let’s come up with a monster.

I read about a monster called Shantu in one book (Baal created it from a panther, a wolf, and... someone else - I don't remember). It's a black cat the size of a unicorn, and it has tentacles sticking out of its sides. It's a perfect hunter - it creates a decoy of itself, and you can't see it until it attacks. It has a 50% chance to dodge!