Flood combat form

"Knowing that monster firing a Battle Rifle at you used to be Kevin from 2nd Platoon is just creepy. That could be me."

- Specialist Archibald Berger, 6th Airborne Division, UNSC Army

A Flood combat form is the primary combat form of the Flood parasite, and one of the most common forms found in early stages of a Flood outbreak. Combat forms consist of infected sentient hosts infected via means of the Flood Super Cell, typically by a pod infector. They serve as the Flood's primary combatants, defending the Flood against attack and securing additional hosts for infection.

Infection and creation
Combat forms are typically created when a pod infector is successfully able to enter a host's body, though this is not the only vector by which hosts can be infected. Flood outbreaks can often be caused by spores or other microbiological vectors entering the host body, or by contact with other forms such as (but not limited to) a Flood Seeder or Infester. In more advanced stages of infection, the need for specific infection forms is decreased as the Flood-infected area converts to a Blightland or Flood hive - by which point, the Flood presence makes up the majority of the terrain in the area, making contact with the Flood Super Cell and the naturally-generated spores an inevitability. Some Flood structures such as the "launcher" specialising in shooting clouds of Spores at uninfected forces, causing them to succumb to the infection without any kind of infection form involved.

As Flood forms, including the combat form, naturally produce the Flood Super Cell (FSC), even being in contact with one can result in infection for an unprotected potential host. Given the combat forms' preference for melee combat, this makes even non-fatal strikes a death sentence, though such infections may progress slowly. However, infection by spore inhalation or infection form is extremely quick, with a host succumbing often in as little as a few seconds.

When conventionally infected by a pod infector, the infector latches onto the host and dig into the host's flesh with a razor-sharp barb-like appendage, injecting the FSC and proceeding to burrow themselves within the host. Typically, the pod infector makes its home within the chest cavity of the host life form, though depending on circumstance this is not always the case. Depending on the host in question, the pod infector will dislodge the host's bones and organs to make room for itself, resulting in extreme disfiguration such as dislocating the host's jaw or - in the case of infected Sangheili - completely snapping the neck. This process can be performed on living or recently-deceased hosts, though often results in the "death" of a living host prior to their re-animation once the FSC takes hold. Some hosts may be attacked and infected by multiple pod infectors. Even if the infection form is removed, the injection of FSC into the generated wounds results in those wounds becoming spore-filled blisters, and cannot save the host from infection.

Once infected, the super cell begins to consume and convert sections of the host body, creating growths and new appendages of new super cell. These growths appear randomly, and appendages produce whip-like tentacles that can be used by the combat form for striking enemies. As this process occurs, bodies take on the appearance (and smell) of decay. Some limbs and sensory organs are preserved in the transformation, and are used for using tools, weapons and vehicles. Damage taken during fighting and infection can be repaired -and the body even augmented - by the controlling infection form, though the combat form is ultimately disposable. The Flood Super Cell is able to arrange itself to mimic any organ needed to keep the host working. Even once the FSC has taken control of the victim, the controlling infection form can often be seen buried within the victim, with the infection form's red sensory appendages poking out of the flesh. Until the body is completely subsumed by super cell growth, these appendages are maintained as an impromptu central nervous system. Some, combat form super cell growths take on a more chitinous nature, akin to armour plating, helping protect the form from enemy attacks.

Hosts can be created from the living or recently deceased, though the infection process typically kills living hosts. Regardless, the process of infection and reanimation is extremely painful. and victims writhe in pain as the Flood takes control irrespective of if they were previously dead or not. The victim may still attempt to cry out from what remains of its mouth and throat even while being controlled, though it is also possible for the infection form to do so using the host's thoughts and memories as a psychological weapon. In some circumstances, a victim may remain fully aware of their present status, unable to do much but watch as their body is controlled by an outside force.

In the case of Private Wallace Jenkins, an infection form had been weakened by eons of stasis and failed to completely take over Jenkins' body. As a result, the former-Marine was able to watch and listen as his body was driven to try and kill or infect those he once considered allies. Jenkins described the presence of the infection form controlling his body as the "other", a strange being without any thoughts and seemingly unaware that the host consciousness was still active inside its body. Jenkins was able to retain a limited amount of motor control of his body, and was able to mime a request for a mirror while in captivity - though the infection form was also able to take back control to attack the Marines surrounding him.

Capabilities
The infection form controlling a host body does not feel pain or fear, though the host is able to feel the physical effect of attacks rendered upon it. In extreme cases, the infection form will resort to self-mutilation of the host body if it needs to, such as breaking its own arms to use the snapped bone as an impromptu weapon. However, the pain inflicted on the host body in this instance may weaken the controlling infection form - though this may be as a result of the unique circumstances of Private Jenkins' infection and not representative of all combat forms. However, the reanimated host is reliant on the infection form for all bodily and motor functions - shooting the infection form will "kill" the combat form, though the body can be re-reanimated if another infection form is able to reach it. As a result, a combat form can be resurrected as many times as is needed, provided the body is still intact enough to be a viable host - to properly kill a combat form, it must be dismembered or disfigured to the point at which it is no longer a suitable host body for an infection form. This can be accomplished through the use of explosive force, gravitic blasts such as those from a gravity hammer, cutting the body up with a weapon such as an energy sword or combat knife or simply incinerating it with plasma or incendiary fire.

Once infected, the infection form is able to absorb all of the host's knowledge and memories. As a result, combat forms are capable of operating firearms, driving vehicles, operating tools and even starships. In the case of the Infinite Succor's infection, infected warriors were able to set up patrols of the ship's corridors to guard the Proto-Gravemind growing in the ship. The Flood's possession of an individual's body allows it to speak with the host's tongue. This memory-absorbtion extends critical knowledge- such as command codes or colony locations. As such, when critical personnel are infected, they are contributed to the construction of a Gravemind.

In combat, combat forms use their whip or scythe-like growths to attack their opponents in melee combat, and are capable of performing superhuman feats such as leaping large distances to cover ground. Even if a melee strike is not fatal, the imparted Flood Super Cell is enough to ensure the target's infection and death. As the infection forms do not feel pain, combat forms are not affected by enemy attacks and will not stop until they are destroyed, or their enemy is killed. Ballistic weapons are notably less effective against combat forms because of this, with SRS99C-S2 AM sniper rifle rounds passing through combat forms with virtually no effect. Targeted shots against the limbs and embedded infection form are effective ways of dispatching combat forms.

Role within the Flood
Combat forms form the majority of the Flood's combatant forces, particularly in the Feral Stage of the parasite's development in which it has yet to acquire enough raw biomass for the creation of a Gravemind or pure forms. During this stage, combat forms are not centrally controlled, and will begin to gather bodies for conversion into more Flood forms. If a location cannot be immediately secured, multiple combat forms may merge to create the Juggernaut and Abomination keymind forms, able to direct local forces in the area until a permanent presence can be established.

When a local biosphere has been completely assimilated into the Flood, typically once the Flood has entered the Coordinated Stage, combat forms cannot be created anymore due to a lack of viable hosts. Due to this, the Flood moves onto breaking down raw biomass into Flood Super Cell, thereby creating pure forms of wholly Flood biomass. Once the number of pure forms reaches a sufficient equilibrium, combat forms are relegated to defensive roles or added to the hive's raw biomass/ calcium reserves. Otherwise aging combat forms begin to eventually begin to spontaneously grow infection forms within a large, bulbous mass on their back. Eventually, this turns the combat form into a carrier form.

Types of combat forms
Virtually any creature can be infected to become a combat form, but the most frequently-used hosts are Sangheili, humans and Jiralhanae. Unggoy and Kig-Yar can be used as combat forms, but this is uncommon due to their weaker body structure. A small number of species are known to be immune to conversion, including the Mgalekgolo/Lekgolo (which are composed of boneless worms that do not have a central nervous system); the Yanme'e, whose exoskeleton lacks the required amount of calcium which renders infection impossible; and the Huragok which is an artificial organism, and therefore believed to be immune. Animals can also be rendered as combat form, provided they meet the Flood's requirements for conversion, though organisms which cannot be converted into combat forms may still find use as raw biomass.

All victims of the Flood's infection, regardless of their physiology, will undergo a similar mutation process. The skin decays rapidly, and changes to the color and texture of Flood biomass as the Flood Super Cells overtake the body. The host's arm bones elongate and grow into whip or claw-like appendages, which will serve as their primary melee weapon in close-combat situations. As the Pod infector now serves as the host's "brain", the head is usually forced aside, and can be severed without any effect on the combat form.

Human form
The human combat form is significantly smaller than other forms due to their hosts' smaller stature. As with other combat forms, it is capable of sustaining massive physical damage before being unusable to the Flood. Although it cannot take as much damage as the Sangheili combat form, the human form has some advantages, being more agile, harder to hit due to its small size, and quicker to melee an opponent. The head of the combat form is pushed to the right side of the body to make room for the Pod infector.

Spartan form
No actual examples of Flood-infected Spartans are known to exist. The ' s War Games combat training deck features simulations of Spartan-IV combat forms, which may have been based on conjecture or on information from actual encounters. Some SPARTAN-IV personnel volunteer for assignment to Flood containment Fireteams, who have routinely dealt with Flood outbreaks in the Post-Covenant War conflicts. Should a Spartan become infected by the parasite, UNSC cryptonym CORRUPTER is declared, authorising weapons of mass destruction for immediate release.

Simulated Flood-infected SPARTAN-IV personnel bear several differences from standard human combat forms. The right arm is converted into a pincer-like, bladed appendage, and the left leg sustains similarly drastic mutations. Exposed parts of the body are covered with what appear to be calcareous plates, and red "muscle" tissue can be seen in the gaps between plates. A large hump or tumor-like growth on the back is apparent, perhaps serving to shield the Pod infector. Perhaps because of the obstructing bodysuit, the typical Flood sensory tentacles do not protrude from the chest cavity. The form appears to retain more of its original silhouette than typical combat forms. Although most of the Spartan's armor is discarded, the components responsible for generating the energy shield are retained. UNSC War Games have also simulated infected SPARTAN-II personnel, featuring mostly intact armor plating except for the neck and head region, where the helmet is cracked and the remains of the victim's skull are visible. These infected SPARTAN-IIs have large Flood biomass growth around their head, with their jaws dislocated to allow the emergence of a Flood tendril.

Sangheili form
The Sangheili combat form is agile, resilient, and capable of utilizing its host's armor abilities such as active camouflage and energy shields to assist them in combat. The Sangheili combat forms are slightly larger than the human form and as such present a larger target. The head of the combat form is typically slung over the right shoulder, the neck bones having been "liquefied" during infection.

Jiralhanae form
The Jiralhanae combat form is a formidable enemy and is more aggressive in combat than other combat forms, as it will charge towards an opponent recklessly; this behavior is most likely a holdover from the Jiralhanae's savage nature and preference for close combat. The Jiralhanae form is more powerful than the human form, but falls short against the Sangheili form. It is bulkier and slower than other combat forms. Since a Jiralhanae cannot be infected until their power armor is destroyed, the Jiralhanae form cannot make use of their host's armor abilities. During infection, the Pod infector often burrows into the mouth of a Jiralhanae, pushing the lower jaw and rest of the head apart to fit into the body. The infected Jiralhanae combat form displays a scream-like expression. This is in contrast to the infecton process of humans and Sangheili, where the Pod infector typically burrows into the left side of the chest of its victim. However this isn't always the case.

Unggoy and Kig-Yar combat forms
Rarely seen in actual combat situations, infected Unggoy and Kig-Yar are more commonly converted into carrier forms or processed for their biomass. These "building blocks" can be used to add to a Gravemind's superstructure or be molded into Flood pure forms.

Unggoy and Kig-Yar combat forms have only been witnessed on two occasions: during in the Battle of the Etran Harborage and the Second Ark Conflict in 2559.

Forerunner combat forms
Forerunner combat forms were described as sickly green with a blotchy hide and long limbs. Remnants of the host's armor could still be found lodged in the combat form.

Gameplay

 * Combat forms can take extensive and sizable amounts of damage before being neutralized. Arms, legs and even heads can be dismembered before they are incapacitated. The weak areas of a combat form are its sensory appendages that normally develop on the upper chest. This is where the Pod infector has nestled, and the body is incapacitated if this area is destroyed by a projectile weapon.


 * In Halo: Combat Evolved, a combat form may fall only to stand up again and keep fighting. This can only happen if it is not damaged enough. In Halo 2 and Halo 3, if the body is not destroyed, combat forms can be revived if another Pod infector crawls into it.


 * Human weapons are generally more effective against the Flood, as Covenant plasma weaponry is designed to debilitate targets by causing burning pain and structural damage to bodies, and the Flood cannot feel pain or be crippled. However, In Halo 3, plasma-based weaponry and melee attacks, formerly weak against the combat forms in the previous two games, are now highly effective. Piercing weapons such as the Sniper Rifle and the Beam Rifle have little effect on combat forms, as both are designed to cause damage to internal organs, which the combat form does not require. At a distance, explosive ordnance such as grenades, rockets, and fuel rod gun projectiles, and ranged weapons such as the Battle Rifle or the Covenant Carbine can perform well against combat forms. Do note that Plasma and Spike grenades should be used with caution, as the combat form will sometimes ignore all other targets and charge players using such weapons at high speed. The Needler can be devastating, as the supercombine explosion will prevent it coming back to life in Halo: Combat Evolved, and will shatter it in Halo 2 and 3. In addition, the Needler's explosions will destroy an entire horde of charging Flood combat forms, similar to grenades and rocket launchers, minus the chance of self-injury. For ranged weapons, it is recommended for players to focus their fire at the sensory appendages that are visible on combat forms as successfully firing at one will immediately bring down a combat form. Dismemberment with ranged weapons is also recommended to prevent combat forms from firing their held weapons. At close combat, it is recommended that individuals acquire close-quarters weapons such as the Shotgun, Energy Sword and Gravity Hammer as they perform exceptionally well against combat forms. The melee attacks from the Brute Shot and Spiker will also do impressively well, no doubt due to the large bayonets that each weapon possesses. Burning combat forms with sufficient amounts of heat (such as that generated by the Sentinel Beam) is one of the most effective methods in any situation, as is the destruction of the torso. Automatic weapons are also effective, though ammo inefficient (it can take up to an entire magazine of assault rifle ammunition to kill a single combat form).

General

 * In Halo: Combat Evolved, combat forms will not disintegrate from successive melee hits when they are dead like in Halo 2 and Halo 3.
 * In Halo 2, all combat forms are also capable of driving and boarding vehicles and are able to do so in Halo 3, though the ability to drive vehicles is lost. They still retain the ability to board slow moving vehicles however.
 * In Halo 2, all of the Sangheili forms encountered use one armor palette; the Minor Combat Harness. In Halo 3 however, the Sangheili Forms will retain its host's armor palette. Strength of each Sangheili Form will be dependent on the ranks of its host; an infected Sangheili Major will be considerably harder to kill than a Sangheili Minor. Killing a Sangheili combat form is often more difficult than killing a human or Jiralhanae combat form, due to the fact that the infected Sangheili often retain their personal energy shielding.
 * Flood combat forms seem to take on physiological and biological changes throughout the Halo trilogy; these changes from game to game could be due to the Gravemind's influence in attempting to create a better Flood soldier or they could simply be graphical updates.
 * While most Flood combat forms wield the weapons of their host's former species, it is not uncommon to encounter them using weapons that their hosts never could have or would have used - human forms with Covenant weapons, Sangheili forms with Jiralhanae weapons, Jiralhanae with human weapons, and many other strange combinations exist, all of which would be rare for their 'living' counterparts.
 * In all of the Halo games, Flood combat forms always hold certain two-handed weapons with one hand, and can actually reload them without doing a reload animation. These weapons include the Shotgun, the Rocket Launcher, the Assault Rifle and others. They can also use the Magnum with one hand and reload it without doing any animation for it. While never shown, it is entirely possible that, in the case of the shotgun, that the flood created a "tentacle" that extended from the host's forearm to pump the weapon.

Halo: Combat Evolved

 * Combat forms will run towards the player when armed. Both human combat forms and Sangheili combat forms will berserk when they have their arm that holds a gun shot off and will rush the player. Combat forms that are unarmed will rush the player by default.
 * Sangheili combat forms can have their head and arms shot off while human combat forms can have their head, arms and chest cavity shot off.
 * In the campaign level 343 Guilty Spark, if you stand on a light bridge, the Flood combat forms will leap onto the bridge and get stuck. They will only be able to move by jumping at you.
 * If you shoot both arms off a combat form in Halo: Combat Evolved it will not be able to attack you and will simply follow you around. Players have dubbed this instance as creating a "Flood Buddy".
 * This is the only game in which a Pod infector cannot revive a dead combat form; instead they may just get back up.
 * Striking a combat form with a vehicle (even a small touch) will result in an instant kill. This is due to the game's physics engine, where a collision with a moving vehicle would kill characters instantly, regardless of the vehicle's speed.
 * All human combat forms are barefoot. This is strange because they wear shoes in Halo 2 and Halo 3. This may however been a design choice to make them look menacing.

Halo 2

 * When using the Grunt Birthday Party skull against the Flood in Halo 2, the effect of the skull will cause the plasma grenade explosion to occur when you shoot the combat form in the chest, where the Pod infector is.
 * Reflecting their enhanced intelligence, human combat forms still wear the armor they had on when they first transformed making it significantly harder to shoot the Pod infector in their chest. Sangheili combat forms can now often have shields which recharge over time. Once the shield is taken down, though, they are very easy to incapacitate.
 * The combat form's performance in close quarters combat has improved. They now attack much faster than in Combat Evolved, deal more damage and can hit enemies behind them with a backwards melee strike. If their tentacled arm is shot off and they don't wield a weapon in their other hand, they will try and melee enemies with their remaining arm, however this attack does no damage.
 * The combat form can sprint towards enemies at a distance (unable to shoot while sprinting).
 * In Halo 2, Flood combat forms can be disintegrated, leaving only pieces of their limbs and shards of armor. This occurs if a combat form is hit by an Energy Sword, blown up by grenades, after many successive melee attacks, if splattered by a fast-moving vehicle, if both of its arms are shot off or if the combat form falls far enough to hit a death barrier.

Halo 3

 * Combat forms can pick up any weapon should it be near them when they "resurrect". They will also pick up two handed weapons such as the Plasma Cannon and Flamethrower if close by. Like other weapons, they will wield it with only one hand.
 * Probably to prevent the player from getting a big combat advantage from Jiralhanae combat forms during the brief time they are allies in The Covenant, or perhaps to prevent enemy Flood combat forms from overwhelming the player, weapons that would normally be picked up when a Jiralhanae combat form "resurrects" are deleted by the game's code, rendering them unusable.
 * An infected Jiralhanae Chieftain will turn into the generic Jiralhanae combat form character model, which is used for all Jiralhanae that become infected, regardless of rank or armor type. This is a pattern shown throughout the games; combat forms are all portrayed with a singular generic character model, depending on the species that is infected.
 * The Jiralhanae combat form is the only combat form in Halo 3 which the host's original head cannot be shot or meleed off.
 * Regardless of gender, an infected human becomes a male combat form. There are no variations between an infected male or female Marine, because there is only one character model for the human combat form in the game.
 * Combat forms are capable of speech in an echoing voice. They usually speak for the Gravemind or quote their host.
 * Halo 3 is the only game in which a combat form can be killed instantly by meleeing them with something other than an Energy Sword, Gravity Hammer or Brute Shot.
 * It is far easier to disintegrate combat form's in Halo 3. Often one or two melee strikes is enough to disintegrate them, compared to the upwards of a dozen successive melee hits required to achieve the same effect in Halo 2.
 * Any combat forms that is killed without being disintegrated can be revived by Pod infectors. The best way to discourage this is to always destroy the bodies.
 * It is noted that using the Flamethrower against pure forms is more effective than combat forms. Pure forms will die almost instantly from the flames, while combat forms may charge at the player while its still on fire.

Halo: Combat Evolved Anniversary

 * Human combat forms receive a graphical update while Sangheili combat forms appear to be using the models from Halo 3. This is most noticeable at the legs, which do not end with Halo: Reach-styled feet. Additionally, all the Sangheili forms appear to be Ultras.

Halo 2: Anniversary

 * Both human and Sangheili combat forms retain much of their host armor. Human forms have the body armor of former UNSC Marines while Sangheili forms all have Minor Elite combat harnesses, much like in the original game.

List of appearances

 * Halo: Combat Evolved
 * Halo: The Flood
 * Halo 2
 * Halo Graphic Novel
 * The Last Voyage of the Infinite Succor
 * Breaking Quarantine
 * Halo 3
 * Halo Wars
 * Halo Legends
 * Origins
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * The Mona Lisa
 * Halo: Combat Evolved Anniversary
 * Terminals
 * Halo 4
 * Terminals
 * Halo: Spartan Assault
 * Halo 2: Anniversary
 * Halo: Fractures
 * Defender of the Storm
 * Halo: Tales from Slipspace
 * Something Has Happened
 * Halo Wars 2
 * Halo: Fireteam Raven