Hydra

Multiheaded menaces, hydras are bestial, amphibious monsters that hunt primarily in water. Swamps, coastlines, lakes, these are their favored hunting grounds. While known for their ferocity, they are best known for their regenerative powers. They can heal their wounds as if by magic. Unless the wound is closed, they can even regenerate lost heads provided they still have at least one head alive. These regenerative properties make their blood valuable for powerful healing potions, and the endless supply of head meat they can grow makes them useful to keep around. They are hard to keep contained though, as a raging hydra quickly becomes a flurry of biting maws that will tear anything in its way to shreds. Even if they can be kept complacent, they require large amounts of food daily, especially when they are regenerating, and need large enclosures to prevent them from going berserk. Despite these many barriers, there have been numerous attempts across history to try and tame hydras. While there has been limited success with young hydras, eventually they all got too strong to control and wandered off, often after eating their captors.