Hydra

Though called many things, the name Hydra became the most well-known term for the extra-galactic race of parasites that battled and nearly defeated the Precursors.
==Background==
==History==
===From Beyond===
===Discovery===
===The War with the Precursors===
===A Subject of Study===
===Reemergence===
===Total Defeat===
==Biology==
===Infection===
===Effects on hosts===
===Counter-measures===
===Forms===
==Combat Behavior==
===Stages===
==Alternate Universes==
===Against All Odds===
===What If?===
In the Alternate Universe of Halo: What If?, the Precursor-Hydra War went on as usual, and the Hydra were defeated. But, when the Forerunners found them, they were soon destroyed by their own Sentinels, and the Hydra were left without opposition. So they spread across the galaxy, and soon found the Flood, who were also left unopposed. All Hydra forces, and all but one hive of Flood forces engaged in an enormous battle in the Ceres system, and the Bujkowe suffered from it. Soon, they managed to activate the Ceres installation, but they escaped on Forerunner ship before the blast destroyed them. The blast from the installation's weapon destroyed all Hydra forces. None were left.
==Trivia==
*They were named the Hydra after the mythological beast which grew back two heads for every one that was cut off.
*Ironically, many Hydra form ideas, such as the Melee and Ranged forms, were created prior to any knowledge of the Flood Pure forms in Halo 3