Hydra (disambiguation)

Hydra may refer to the following:
 * Hydra - A UNSC weapon.
 * Hydra system - A colony system of the UNSC.
 * Hydra System Massacres - A group of conflicts in UNSC history.
 * Hydra (code) - A UNSC code word for biological threats.
 * Operation F: Hydra - The final chapter in Halo: Spartan Assault.