Haos (final)

Chapter: C5 · The Underwater Facility: the Ducts, Haos and the Escape
Where: 5-4 Emergency Escape Route: the final chamber, with containers and high platforms

Weak point

The 2 orange or red growths on the sides of its back; then the cocoon and the 3 hearts

With his arm crushed, Piers injects himself with the C-Virus: he can no longer use weapons, herbs or items. He only fires bio-electric shots (the charged one stuns and damages; normal ones are more accurate on the growths) that cost vitality, which regenerates on its own. Chris uses his normal weapons. In this phase, damage anywhere but the growths does nothing. Attacks: hand smash, long swipe, grab and crush = instant death, tentacles that snake around corners, a drag under its body, slime bombs (4-5 green balls that grow on the floor and explode: shoot them; some stick to the ceiling and drop as you pass) and a body slam (extreme damage). When hurt, its lower half detaches, scurries around and explodes a few seconds later.

Reward

End of Chris's campaign (achievement Duty Calls). Medals Escaped from the giant B.O.W. and Said farewell to your partner.

Kite it around the room: it's slow. There's ammo in boxes around the room, and the slime bombs sometimes drop some. No source publishes its health.

Step by step

Before it: 4 wooden crates + 3 boxes. Bring Flash Grenades and acid rounds. Press the floor panel to start.
Stun it first: a Flash Grenade stuns it instantly; so do a few acid rounds, some shotgun shells or Piers's shots.
Get behind it and pop a growth. You usually get one per stun: stun it again for the second.
With both growths gone, a large organ shoots out of its lower chest and explodes if you touch it: shoot it and keep away.
It crystallises into a cocoon: break it with a full shotgun or machine-gun magazine before it regenerates (leave it alone and it regenerates fully).
It falls on its back: run in and do the special melee to slash one of its 3 hearts. When Piers says it's your chance, go.
It climbs onto a container and cocoons again: up there it can't be damaged. When it comes down, repeat.
3rd heart (scripted): Chris is left Dying. Crawl to Haos and use the partner button while Piers holds on with his own QTE. Both have to succeed.
Afterwards: open the door for Piers. Piers fires his charged arm up close at the organic barricades while Chris covers him; it's timed, so don't stop to fight. At the 3rd barricade, look down to the right: Serpent Emblem #20, above a red light (missable once you pass).