A Bievilerd is an alien creature from the planet Ondar. It's a bird-like creature that looks like a living stealth bomber; entirely black with huge wings, lifeless orange eyes, and between the wings is a huge mouth full of small, razor sharp teeth and a silver tongue. It can fly with out much effort because it doesn't have to flap it's wings all the time. Visser Three morphs this creature in Book #45: The Revelation.