A huge plant like thing, made of a collection of Flood. many think that this actually controls the flood, but it isn't a fact. Graveminds form when the flood has been released on a planet (in this case Delta Halo)for long enough, and is probably the collective minds of everything that is taken by the flood. the "keyes blob" from the original halo was probably an early gravemind. He tricked John ( Master Chieffor n00bs) and the Arbitor, and took a ship to High Charity. In the end, he asks the rampant Cortanasome questions. Cortana is such a whore.
