Halo Season 2: What Is The Flood?

Warning: The following article contains major spoilers for Halo Season 2, Episode 8, “Halo.”

The Flood just made their live-action debut in Halo Season 2 – so, what exactly is the Flood? And what do we know about these iconic baddies from the Halo video games?

Related: Does Halo Season 2’s Finale Have a Post-Credits Scene?

The Flood in Halo Season 2, Explained

As depicted in Halo Season 2, the Flood is an ancient species of parasitic organisms that take control of and physically mutate their infected hosts. Another old-timey civilization, the Forerunners, seemingly understood the threat the Flood poses, as they sealed away their underground lab on Onyx to prevent the Flood spore samples within from spreading. This ultimately fails, however, as Dr. Catherine Elizabeth Halsey and Commander Miranda Keyes unwittingly unleash the spores on ONI’s secret headquarters after retrieving them from the Forerunners’ lab, sparking a mass Flood outbreak.

The Flood’s takeover of the ONI base is gradual. At first, they take control of ONI personnel (such as Miranda’s fellow scientist Janine) via spores and small, slug-like Infection Forms. But as the parasites’ number of infected hosts grows, they begin assimilating their victims through violent physical contact. In practice, this looks somewhat like a stereotypical zombie attack, although Halsey’s infection late in Episode 8, “Halo,” suggests spores (not bites) remain the Flood’s primary means of infection.

Related: Halo Season 2’s Ending, Explained

Either way, it’s all very gruesome – not least because of the newly minted Flood Combat Forms’ hideously deformed bodies. Not only are they typically covered in fleshy growths, but some also sprout powerful tentacles they can whip around in battle. Augmentations such as these make the Flood’s forces – which are all part of the same hive mind – a handful, however, they’re still vulnerable to standard-issue UNSC weapons. Soren-066, James Ackerson, and Kwan Ha prove this at various points throughout “Halo,” dispatching Flood Combat Forms with both pistols and higher caliber firearms.

Kwan also briefly takes advantage of the Flood’s only other known weakness in Halo Season 2: mystical intervention. Surrounded by the Flood, Kwan has a vision of enigmatic shaman The Mother, who temporarily keeps the infected hosts at bay via her connection to Kwan’s ancestors. It’s unclear at this stage whether this was a one-off occurrence, or whether Kwan herself will be able to pull off a similar feat in future Halo episodes. If the latter, it explains why the Flood is keen to add Kwan to their ranks.

What Do We Know About the Flood From the Halo Video Games?

That’s all we know about the Flood from Halo Season 2 – but what do the games have to tell us? Quite a bit more, as it turns out. For one thing, gamers already know the Flood has a quasi-leader, the Gravemind. This grotesque Venus flytrap-like creature is the central vessel from which the Flood’s shared intelligence flows. The Paramount+ series hasn’t yet introduced the Gravemind, although Kwan’s visions of a “monster” headed the galaxy’s way almost certainly refer to the beastie.

Related: Will Paramount+’s Halo Get a Season 3?

The Halo video games’ canon also establishes early on that the Forerunners created the Halo Array as a last-ditch weapon against the Flood. Once activated, the Array’s seven rings wiped out all sentient life in the galaxy, cutting off the Flood’s food supply and leaving them to starve. Not even this was enough to put the Flood down for good, though – and that’s why they’re among the most dangerous enemies Halo protagonist the Master Chief and his allies have ever faced.

Halo Season 2 is currently streaming on Paramount+.