The Flood are one of the most pervasive and dangerous enemies the player faces in the Halo series. Capable of infecting all living matter at a juggernaut’s pace, they seek to infect, mutate, and dominate all life in the galaxy.
Through the process of evolution, mutations in various life forms, and the tweaking of the Gravemind, the Flood has developed a number of different forms. Each serves a vital role in the effort to transform the galaxy, with some being stronger than others.
Updated April 28, 2024, by Ben Painter: Halo is one of the most popular gaming franchises of all time, and this is partly thanks to one of the main villains, the Flood. This alien parasite is a common enemy throughout the early games as they look to infect their way throughout the galaxy. Now, the Flood is back in the mainstream after featuring in season 2 of the Paramount+ live-action Halo series. So it is only right that every flood form in the series is revisited.
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26 The Hive
Serves As A Base For Flood Life
- First Appearance: Halo 2
A Flood Hive is where the Flood grows and develops, and it is an important part of the life-cycle of the symbiotic species. A hive develops once a viable Gravemind has been developed and the Flood has access to a sizable population.
Since this stage of the Flood cannot attack, it cannot be considered dangerous and is thus weakest of all the forms of Flood. An example of a Flood Hive can be found in the Covenant capital of High Clarity in the Halo 2 campaign.
25 Spores
The Most Basic Infection Form
- First Appearance: Halo 2
The most basic form of Flood that could be considered dangerous, Spores are microorganisms that are capable of infecting and suffocating living beings. These aren’t typically used by the Flood to create new hosts, but they have proven useful.
Any being that inhales the spores will suffer a slow mutation process that does not manifest as much externally. It’s less effective compared to other infection methods, though the Flood will sometimes disperse spores atmospherically to assist their efforts.
24 Tadpoles
Less-mature Pod Infectors
- First Appearance: Halo 2
These little guys appear in Halo 2 exclusively. They’re a less mature stage of Pod Infectors, being smaller and are only seen in tanks in a research lab. It’s unclear what their capabilities are, if any, though it’s likely they serve a similar function to Pod Infectors.
23 Pod Infectors
Small Squid-like Creatures That Are Easy To Kill
- First Appearance: Halo: Combat Evolved
Pod Infectors are by far the most common form in existence and are responsible for infecting other life forms. These small squid-like beings swarm over opponents until they can penetrate the victim’s flesh and wrap around the spinal column.
It then begins spawning Flood Super Cells inside the host and rapidly mutates them into a desired form of Flood. In large numbers, they can be very dangerous, but individually they are little more than a nuisance.
22 Seeder Infectors
Airborne Pod Infectors
- First Appearance: Halo Wars 2
Seeder Infectors are similar to Pod Infectors in that they infect other organisms and quickly transform them. The difference, and what makes them a little more dangerous, is that they are airborne. They can also spit out bone fragments of their victims as a weapon.
21 Carrier Form
Infected Carriers That Burst
- First Appearance: Halo: Combat Evolved
Carriers are charged with spawning more Pod Infectors and keeping them safe during delivery. They will seek out life forms, explode, and simultaneously emit Pod Infectors to swarm the now weakened target.
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They’re slow and function as little more than mobile incubators. But in close proximity, they are a major threat.
20 Burster
Carrier Forms That Bury In The Ground
- First Appearance: Halo Wars 2
The Burster is similar to the Carrier in that it transports Pod Infectors and Spores into battle before detonating upon an enemy. The main difference, and why they’re more dangerous, is that they burrow underground before emerging and exploding.
19 Flood Swarm
Flood That Has Infected Airborne Animals
- First Appearance: Halo Wars
These are birds, bats, and other airborne animals that have been infected. The Flood Swarm travels in groups to overwhelm opponents with sharp projectiles. They are very weak, and a single Swarm is hardly a threat, but in a cluster they are a nightmare.
18 Spawner Form
Flood Transporter
- First Appearance: Halo Wars 2
Spawners are essentially troop transport for the Flood. They sit on the edges of battle, spawning an endless wave of Pod Infectors. When their life is threatened, they’ll spawn a unit meant to counter that threat. This allows them to keep sending waves of mini enemies and have the means to keep themselves alive.
17 Dispersal Pod
A Drop Pod For Flood forms
- First Appearance: Halo 3
The Dispersal Pod is essentially the Flood's answer to the ODST Drop Pod. In these pods, Flood species will drop down in packs to surprise their enemies in large numbers. The most notable example of this happening is during the Halo 3 campaign, when Combat Forms were dropped onto the Master Chief to prevent him from activating the Halo array.
They crash onto land with great strength. Usually, the Flood isn't presented in such ways, but in an act of desperation, the almighty Gravemind had no choice.