The Tjesu heru is a giant two-headed serpent with four dragon legs.

The Kane Chronicles

The Throne of Fire

When Carter and Sadie invaded the 18th nome and were caught, Vladimir Menshikov throw his staff which formed into the Tjesu heru, Set refused to destroy it allowing it to attack the Kanes, which resulted in a fight that the Tjesu heru was destroyed by Sadie but not before biting Carter nearly killing him.