The recent beckoning from Halo: Escalation about upcoming Halo 5: Guardians plot points is… intriguing.
Covenant-Human Alliances, UNSC Spirit Of Fire, the Flood, Ur-Didact, Spartan-II Blue Team… a lot is spiraling toward a cataclysmic and memorable game.
So my theory, being the rumored, or rather destined, darkest Halo game to date… even darker than Halo: Reach… we may see a return of the Flood.
I am just appreciating the fact, that we get another crack at those slimy, sons-of-Precursors… and with it new Flood forms.
Canonically, the Flood Gravemind having succumbed to his defeat, on Installation 00, at the hands of Thel 'Vadam (Arbiter/Kaidon), John-117 (Master Chief/Spartan-II), Avery Junior Johnson (Sergeant Major/Spartan-I), 343 Guilty Spark (Chakas/Monitor) and Cortana (Smart-AI)… has learnt from his experience with Modern Humanity and the Covenant Empire… this incarnation of the Flood Primordial/Gravemind has developed new, potential solutions to dealing with their armaments, as well as re-newing some older, more valuable assets to deal with the Forerunner and Promethean.
Now I am suggesting obviously the old forms already seen, both in Halo: Combat Evolved, Halo 2, Halo 3, Halo Wars, Halo 4, Halo: Spartan Assault… as well as the unused concepts like the Flood Dreadnaught… need to return. As well as the older, more versatile and dangerous ‘class-7 Flood Forms’ could be based off of the Forerunner Saga, by Greg Bear… the new ones could be a volatile (explosive), or more probable a corrosive (acidic), Flood Form. The Form when killed could blow up, and spurt a corrosive acid, or spores, damaging, or perhaps infecting, nearby enemies… this would be akin to their ‘weaponry’ being purely DNA/body orientated… Melee (Fists, claws, tentacles etc.), Hardened Flood Biomass/Spines/Spikes (Pure Form Ranged), Acid…