The Flood

&nbsp The Flood's origins are unknown, even to the all-knowing Forerunners. Flood biomass is composed of an undifferentiated cell-type that is referred to as the Flood Super cell [FSC], which can be described as approximating "thinking muscle." The FSC closely resembles neurons or glial cells in structure. The Flood can arrange these cells to mimic any organ it might need.

Evolutionary Stages:

1) The Feral stage is the lowest of a symbiotic sustained from: communicating via pheromones and with the natural instint to hearvest enough calcium to establish a viable Gravemind.

2) The Coordinated Stage is when the Flood becomes truly dangerous; it now takes orders from the Gravemind that was created in the first stage.

3) The Intersteller Stage allows the Flood to use hosts to take control of technology and spread throughout the Galaxy to infect more hosts.

4) The Intergalactic Stage is the last know stage the Flood enters, during which it utilizes all captured technology to seek uninfected Galaxies for new Flood that arrived in the Milky Way originated from an Intergalactic level Flood.

The different form of the Flood parasite are:

1) Infection form: The lowest next to the spores themselves, Infection forms crawl under the skin of targets and infect them, turning them into Combat or Carrier forms.

2) Combat forms: There are standard Combat forms, that were originally UNSC Marines or Brutes, then there are Shielded Combat forms, that were originally Elites.  The Combat forms have been seen since Halo Combat Evolved, the Shielded Combat forms weren't seen until Halo 2.  There are also Grunt Combat forms seen in Halo Wars.

3) Carrier forms: Carriers are filled with multiple Infection forms, and explode to release them.  When they get to close to enemies or are injured, they detonate.  The explosive force from Carriers can not only launch Infection forms around the battlefield, but they also help in killing the Flood around them.

4) Pure forms: There are 3 different Pure forms.  The Stalker can mutate back and forth between Ranged & Tanks.  The Ranged fires a barrage of needles at targets, and can change back into a Stalker when ever it needs to get to a safer area.  The Tank is like a Hunter, just without a gun or shield, the Tank can spit out Infection forms from its mouth space, they can change back to Stalkers when ever they actually want to shoot something.

5) Prophet form: There has only ever been one Flood Prophet seen in the games.  In the Battle of Installation 05, the High Prophet of Regret was reanimated as a Flood Prophet.  The Gravemind used him and 2401 Penitent Tangent to make a temporary alliance with John-117 and Thel 'Vadumee, in stopping the lighting of Installation 05.

6) Brain form: There has only ever been one Flood Brain seen in the games.  In the Battle of Installation 04, CPT Jacob Keyes was mutated into a Flood Brain form.  John-117 and Cortana had to re-infiltrate the 'Truth and Reconciliation' to recover CPT Keyes or at least the command codes to self destruct the 'Pillar of Autumn' and stop the Flood from escaping, and stop 343 Guilty Spark from lighting Installation 04.

7) Proto-Gravemind: There has only ever been one Proto-Gravemind seen in the games.  During the search for Prof Ellen Anders on the Forerunner Shield World, during Mission 09 (The Flood).

8) Gravemind: There has been one seen in the games and one seen in Halo Legends. The Gravemind in the games made its first appearance in Halo 2 & made a partial appearance in Halo 3.  Theoretically, there can only be one Gravemind at a time, so if one is killed another may form shortly thereafter if the Flood retains sufficient biomass.  It appears that one existed over one hundred thousand years ago but was destroyed by the first firing of the Halo Array.  Another was recreated afterwards in the depths of Installation 05.  Upon its release, it showed remarkable understanding of Forerunner technology, even going so far as to capture the resident Monitor, 2401 Penitent Tangent, manipulating the installation's teleportation system, and understanding the purpose and intricacies of the Halo Installations.

"I have beaten fleets of thousands! Consumed a Galaxy of flesh and mind and bone!"

