The Flood Stalker Form is a crustacean-like Flood Pure Form that specializes in stealth and agility. It is apparently made from the re-casted bones of dead enemies. It will frequently mutate into either a Ranged Form or a Tank Form when the need arises. This form sits low beneath your field of view and their attacks can go widely unnoticed until you look down. They are able to crawl on walls and ceilings with ease, and are capable of making enormous jumps much like combat forms. A possible flaw in its AI is that it has been observed to rarely attack players, and normally prefers to mutate itself into one of the two other Pure Forms. It appears to attack more often on the levels Cortana and Halo. Even if they do attack, they are not as strong as the Ranged or Tank forms, making it the easiest of the three to dispatch. Oddly, on Easy, these creatures do NOT attack.
Stalker forms are very weak, with a single blast from a Shotgun, a simple melee, slash from an Energy Sword, or a few bursts from an Assault Rifle capable of bringing one down. To make up for their fragility they are incredibly fast and agile, so great accuracy is needed. If you can get up close, a single melee attack from any weapon, can usually bring one down. Any weapon will do, but grenades do it much better, because their spindly physique makes them harder to hit. When playing on higher difficulties, they have a habit of mutating when they're stuck. The grenade appears to be absorbed but does not detonate, making it useless. If you hit them with an Incendiary Grenade or a Flamethrower, they will instantly jump away and scream, then they will die after a few seconds of burning. The name "Stalker" is represented quite well on both Cortana and Floodgate, as they blend in quite well with the surrounding Flood-ridden walls. It is easier to kill them at long range before they transform into the much more powerful Tank Form. One is noticed straight away at Floodgate, which is on some crates, though it is hard to see a bit cause it blends with the crates and with the environment (its really hard to see with everything going around).
Floodgate: Uncommon (en route to crashed ship)
The Covenant: Very Rare (just two seen as allies that later mutate into Tank forms anyway)
Cortana: Very Common (all over the place)
Halo: Very Common (climbing up the ziggurat)
- Stalker forms can be killed while mutating. As a result, the corpse left behind usually takes the appearance of the Stalker and the Ranged or Tank forms merged. Occasionally, they will have a very extended appearance with strange physics properties in-game.
- Oddly, Stalker forms, on easy will NOT attack, at extremely rare times will attack, dealing little damage.
- While annoying, agile, and creepy, the Stalker Form rarely attacks you in the levels it appears. When it does, it does not cause as much damage as it does not possess the skill set (strength, weapon compatibility, shooting needles) that the other Flood forms have. Stalker Forms are more likely to mutate into one of the other Pure Forms than to attack in open combat against a player.
- The Stalker Form is notable for being extremely cowardly when approached, as it will attack a player if they are unaware of the Stalker's proximity.
- The rear part of the Stalker Form seems to be parts of a Human torso.
- They are first seen on Floodgate.
- They cannot use any weapons apart from their pincers.
- Stalkers tend to lunge at their foes on higher difficulties, although this does not increase the damage received compared to a normal attack.
- Stalker Forms can transform into a Tank Form and a Ranged Form.
- On the Halo 3 level Halo, there seems to be an endless supply of Stalker Forms traveling up the sloped shaft in the center.
- When they have nothing to attack, they will normally scurry around waving their pincers.
- Stalker Forms have a habit of destroying equipment, namely the Deployable Cover. This can be quite annoying on higher difficulties where the player must deploy equipment to survive, especially on the level Cortana
- On The Covenant, the allied Flood Tank Forms will sometimes mutate into Stalkers in order to attack Jump Pack Brutes. When a Brute is directly overhead, the Stalker will jump a great height in order to attack it. Though it is rarely successful, upon success, the Brute's jump pack will immediately deactivate, sending the Brute and the Stalker crashing to the ground, or down the bottomless pit.
- This is the only Flood Form to get the "assassination" reward.