Hydra

The Hydra was a flying Locust creature that is similar to the Reaver. At least two Hydras existed; one was the personal mount of Locust high priest Skorge.

Lightmass offensive
After the defeat of the Locust Horde during the Lightmass Offensive, one Hydra along with its rider escape the destruction of the outer Hollows.

Hollow Storm
After the defeat of the Locust Horde, Skorge, the high priest of the Kantus monks, used the awakened Riftworm to destroy Sera's cities on the surface. On his personal Hydra, Skorge led the Riftworm to Tollen and Montevado, destroying the cities. During Operation: Hollow Storm, Skorge, atop his Hydra, led the Riftworm to Ilima, sinking it too. After the death of the Riftworm and the attack on the Queen’s palace, Skorge attacked the retreating Gears on the Reavers but was stopped and killed by Delta-One on the Reavers.

Behind the Scenes

 * The Hydra in Greek mythology is a serpentine creature with multiple heads, which would grow two more heads if one was cut off.