Jack (morgue)

Chapter: 2 · Main House · Processing Area
Where: Processing Area Morgue: a pit with a central brick pillar and hanging body bags

Weak point

Only while he is down or his head is open (the "tumour"); on his feet, bullets only stun him

It starts when you take the Red Dog's Head on the upper level of the Morgue: Jack throws you into the pit. Keep 2–3 slots free for the Chainsaw and carry 2–3 First Aid Meds. He has about 4500 HP and this fight ignores the difficulty rank. While he walks he only takes stun damage; real damage lands when he is down. Bullets break that animation after the first shot and melee doesn't, which is why the chainsaw is the phase 2 weapon. The pit has a First Aid Med on the NE bucket, a Herb in the breakable crate to the south (Strong First Aid Med on Easy) and the Chainsaw behind the mesh. Craft Enhanced Handgun Ammo first (1 Strong Chem Fluid + 1 Gunpowder = 10 rounds).

Reward

The Red Dog's Head, the last of the three dog heads. The Chainsaw cuts the door blockade and stays in the Morgue.

About 4500 HP, no difficulty rank; each body bag has 1000 HP and bursts from Jack's hits. His first weapon is an axe according to most sources (others say a shovel or a hatchet). Madhouse: the Circular Saw (ZL + ZR held) kills him in seconds; without it, body bag → one Enhanced Handgun Ammo headshot → shotgun, no chainsaw needed.

Step by step

Phase 1: circle the pillar. When Jack walks past a body bag, kick it into him (A next to the bag): it staggers him. The angle matters.
With Jack staggered, shoot his head: about 10 handgun shots bring him to his knees, or 3–5 rounds of Enhanced Handgun Ammo. When his head bursts into a mass of flesh, switch to the shotgun.
If he grabs you or stabs you, shoot him so he lets go. Out of ammo you can survive by dodging until he goes for the shears, but it takes minutes.
Phase 2: he rips the mesh open and takes a pair of giant motorised shears. The Chainsaw is right next to it: grab it at once.
Block with the chainsaw (L): a last-moment block staggers him. Head-on clashes cancel both attacks and nobody takes damage.
The loop: body bag into him → 2–3 swipes (ZR) → he kneels and the tumour pops out of his head → ZL + ZR and hold to drive the saw into it.
When the saw's light turns yellow and then red, the engine stalls: rev it with Y, always with the pillar between you.
He mutates about 3–4 times on Normal. Near the end he knocks down the central pillar and you have less room: keep the pressure on while his face is open.
"Duck If You Love Life" achievement: when he runs at you and strikes from above with the shears, crouch (press the right stick). His other attacks still hit you. This is the only chance: save before taking the head.