The Flood

"The installation was well-conceived. It is surely the only way to end the Flood threat" -343 Guilty Spark, Halo: Combat Evolved

The Flood is a parasitic species featured in the Halo franchise.

For the Halo Reach review, click here.

Characteristics
The Flood is a parasitic organism that finds hosts in other species to reproduce and grow. The Flood is considered the greatest threat to sentient life in the galaxy. The Flood are incredibly dangerous because they can adapt to almost any enviroment and all of their soldiers are expendable because they are so easy to produce.

The Covenant built the Halo rings as a weapon against The Flood in case of an outbreak, which during Halo: Combat Evolved, The Covenant failed to stop The Flood themselves. The Halo rings however would destroy all life in the galaxy if all activated at once.

The Flood has many stages and forms to maximize its effectiveness, some of these forms are:


 * Infection form - This is the first stage of The Flood, this small type of Flood is easily killed and little threat alone but in packs can easily take down and consume a squad of Marines or Covenant.

But each form has a similar combat style in which they swarm the nearest enemy until the enemy is killed and then they swarm the next enemy. The Flood once taking over an area will cover the area in Flood biomass, so the commanding Gravemind can create more Flood forms.
 * Carrier form - This form is a type of Flood that holds many Infection forms inside its bloated body. Carrier forms explode when damaged which can kill anyone near them.
 * Combat form - These kinds of Flood can vary in different strengths depending on the host. Combat forms are created when an Infection form takes a Human, Elite or Brute as a host. Only these three can become combat forms because of their size as Grunts and Jackals are too small and frail.
 * Pure form - These types are not created by Infection forms but are composed of Flood biomass. Because of this the Pure form can shapeshift into tatical forms, such as the Tank form is for attacking while the Ranged form is more for defending positions.
 * Gravemind - A Gravemind is the final stage of the Flood cycle and is the leading intelligence for all of The Flood. Graveminds are huge in size and couldn't be destroyed be a squad of Marines or Elites. A particular Gravemind is the main antagonist in Halo 2 and 3.