A hydra wand is any wand that has a sliver of land hydra claw, a sliver of hydra scale, or a shard of hydra tooth in its core.
Hydras
Hydras are large snake-like creatures. Their most famous characteristic is that they have several heads on the ends of long and sinuous necks. Hydras are very difficult to kill for if one head is cut off, then two will rapidly grow in its place. There are two main families of hydra: land hydra and water hydra.
Land hydras are native to the Blood Mountains of Faerie and passed through the Lonely Chasm portal from there to Mount Korab in Macedonia. Probably entering this world in the form of eggs or while very young and still small, land hydras then spread into the mountains of Greece, Italy, and Turkey. On the other hand, water hydras undoubtedly swam into our world via the underwater portal just inside the Straits of Gibraltar. The much rarer now, they may still be encountered in the Mediterranean and Black seas.
Land Hydra and Water Hydra