The
Flood are fictional
parasitic alien life forms in the
Halo video game series created by
Bungie. They are introduced in as a second enemy faction alongside the
Covenant, and return in sequels
Halo 2,
Halo 3,
Halo Wars and as a gametype in
Halo 4. The Flood are driven by a desire to infect any sentient life they encounter, and are depicted as such a threat that the ancient
Forerunners were forced to kill themselves and all other sentient life nearly 100,000 years ago in an effort to starve the Flood to death.