Okay, this can be in Halo 4 even if the Flood do not make an appearance- it doesn’t have to be canon. Anyways, iv’e mentioned it before, but iv’e expanded on the idea. So their are three scenarios for flood mode, Installation 04 (Covenant), Earth (Humans), and ??? (Precursors/Forerunners). You start the game as an infection form swarm, you control around 7 of the little buggers, and your goal is too infect 3 enemies so you may evolve into a Combat form. Once you are a combat form, you must kill 10 humans, and drag their bodies to a zone similar to the ones in Stockpile, to form a proto-gravemind. Once the proto is made, you must make it grow, so you evolve into a Carrier form to spread the infection. Once you blow, you respawn as a carrier and keep spreading. Once you have 20 more bodies, you carry them to the proto to make it grow even more. It’s now a real Gravemind, and now can choose your next evolution: Stalker, Ranged or Tank form, each have their own form trees.
What do you guys think?