Pod infector/Gameplay

The Flood infection form is one of the easiest creature to eliminate in the Halo series, requiring only one shot form any weapon. However, as easy as it may seem, a swarm of Infection forms can also be a formidable threat to the unwary individual.

Combat
In order to overwhelm hosts, infection forms attack in large swarms, leaping at any nearby targets and attacking with their claws and tentacles. If the victim's shields are active, as explained earlier, the infection form will burst. However, the sheer force of numbers can sometimes deplete a victim's shields, allowing these Flood forms to take control of the host's body. While individual infection forms are weak, in large numbers they can exert a surprisingly powerful force, being able to shatter doors made of Forerunner alloys.

A single round from any weapon will burst an infection form. For this reason, automatic weapons are recommended. Dual-wielding Plasma Rifles, Brute Plasma Rifles, Spikers or using a UNSC ballistic weapon all work well. The Battle Rifle with its bursts fire can be quite effective and the Shotgun can work well too when shooting at large groups closing in. Try to avoid using weapons such as M6 Handguns, as their rate of fire is very low. Also, try to use Grenades, but be careful as sometimes Infection Forms can be stuck with Plasma Grenades and may harm you when it gets close. In Halo: Combat Evolved, automatic weapons like the Assault Rifle and Plasma Rifle are good on them as well as the Plasma Pistol, and the the Needler can turn out to be a very good alternative as the needles have homing ability. Be careful though, do not stick too many Needles on one at a time while they are close as if you do it will explode and effect you most likely depleting your shields. The best way of using it is to fire a single shot at each Infection Form, which is enough to kill them. SMGs are incredibly effective for taking on swarms of infection forms with its large magazine size and impressive rate of fire. The Sentinel Beam is also extremely effective and can swiftly obliterate entire swarms of infection forms at long ranged distances. Infection forms are spawned from bulging, sac-like pods in Flood hives, called Flood growth pods. It may be tempting to destroy these sacs, but it is actually more advisable not to, since destroying them will not kill the infection forms inside.

Halo: Combat Evolved

 * It is best to leave the Infection forms for last and focus on larger threat such as the Combat forms and the Carrier forms.
 * Shooting a swarm of Infection forms can set off a chain reaction killing a couple of nearby Infection forms within that swarm. For example, in a swarm of three Infection forms, killing one could incidentally kill off the other two if they're close to one another.
 * An Assault Rifle is the best tool to kill of a swarm, followed by the Plasma Pistol and the Needler (to kill one at a distance). Reserve the rest of the weapons for the Combat forms.
 * The Assault Rifle is the best gun. Additional ammunition is plentiful in the Flood campaign levels. Make full use of it.
 * The Needler is fun to use on the Infection forms from a distance. The homing needles makes it easier for the player to not aim properly and escape at ease.
 * If all else fails, melee the Infection forms.

Halo 2

 * Unlike in Halo: Combat Evolved above, there is no "chain reaction" effect when shooting a swarm of Infection forms. As such, the player must use considerable effort to kill the swarm. A SMG would generally be sufficient for such job.
 * Similarly to the above section, it is harder (and potentially impossible) to melee the Infection forms. As such, engage them at a distance.

Halo 3

 * Much of the gameplay tips in Halo 2 section above can be used in Halo 3.
 * The SMG and the Assault Rifle are the best tool to kill of the Infection forms due to their ammunition count.
 * Fire weapons, like the Incendiary Grenades and the flamethrower, are very effective against the infection forms.