User blog comment:Ravager134K/The Chimera vs Aliens/ Predator/ The Flood/ The Covenant and Psuedo Arachnids/@comment-208.108.81.7-20120201135733

the flood are like parisites that feed then use the bodies of sentitnt beings in halo. they have a leader called the gravemind which has the knowledge of all the species that the flood has ever consumed. including a few forerunners