The name is Greek, for 'to go both ways'. The Amphivena has two heads. One on it's shoulders and another at the end of it's tail. It is said that they are capable of running backwards of forwards equally well in either direction. They are common through out north Africa and live in the desert.. They can run with great speed, and agility. They often hide and then snatch up prey with their tail head. Their eyes are known to glow in the dark, often the approaching eyes is enough to startle their prey long enough to finish them off. One of their more humorous tricks is that one head can bite the other and make a loop that they can roll with.
Their bodies may not have limbs or wings and be entirely serpentine like a snake, or have two legs and a set of wings just like any wyvern like creature. The tail head may vary from complete sentience or just a maw controlled by a single brain.