How to Get the Mutant Injection in Warzone Haunted Hollow (EMF Reader Ghost Easter Egg)

The Mutant Injection is a hidden killstreak on Haunted Hollow that transforms you into a Mangler from Zombies for a short time. You earn it by finishing the EMF Reader ghost hunt at the Research Center, a self-contained Easter Egg that only needs two items and a few minutes.

Quick answer: Grab the EMF Reader from the server building southeast of the Research Center, pick up a weapon with a Thermal Optic, then use both to find and shoot three spirits. The third kill drops the Mutant Injection.

Image credit: Activision via YouTube/@Mr. Fishy McFish

What you need before starting

The whole hunt takes place in and around the Research Center, so you can complete it without touching the rest of the map. Two items are required, and one of them already spawns nearby with the right attachment.

The EMF Reader, a Tactical item that measures how close you are to a spirit.
A weapon fitted with a Thermal Optic, needed to see the ghost once the room goes dark.

You can build a loadout with a Thermal Optic ahead of time, but there is a ground weapon inside the Research Center that already has one attached, so a custom class is optional.

Complete the EMF Reader ghost hunt

Head to the building southeast of the Research Center and go to its bottom floor. Look for the server room and pick up the EMF Reader from a desk in the corner. Grabbing it stores the item in your Tactical slot.

Locating EMF Reader — The EMF Reader sits on a desk in the corner of the server building's bottom floor. Shown at 00:40 in Invoked by Red’s video. Image: Treyarch

Move to the main Research Center building and go up to the top floor. Toward the center of the south portion, next to a whiteboard, you will find a Voyak KT-3 assault rifle already equipped with a Thermal Optic. Pick it up so you can spot the spirits.

Acquiring Thermal Optic Weapon — A Voyak KT-3 with a Thermal Optic spawns by the whiteboard on the top floor. Shown at 01:00 in Invoked by Red’s video. Image: Treyarch

Pull out the EMF Reader and walk through the Research Center to track a spirit. The reader shows a Low, Medium, or High signal based on your distance. Keep moving until the reading climbs to 9.99, which means the ghost is in the room with you.

When the signal maxes out, the room turns black. Switch to your Thermal Optic and aim down sights to find the ghost. It appears as a random object with a glowing particle effect, often floating in place. Shoot it to score the hit and send the spirit to a new spot.

Shooting First Spirit — A glowing spirit spotted through the Thermal Optic, awarding +100 Spirit Found when shot. Shown at 00:36 in Kokopelli’s video. Image: Treyarch

Repeat the track-and-shoot process two more times for a total of three spirits. Each hit relocates the ghost, so use the EMF Reader again to close in on the next one.

You have a limited window to hit each spirit. If you take too long, a jump scare triggers and the ghost moves to another location, forcing you to start tracking that one again.

Shooting Third Spirit & Reward — Shooting the third spirit ends the hunt and drops the reward loot. Shown at 00:47 in Kokopelli’s video. Image: Treyarch

Claim the Mutant Injection reward

Shooting the third spirit ends the hunt and drops a pile of loot on the floor. That drop includes cash, a Psych Grenade, and the Mutant Injection killstreak device. Walking over the loot and picking up the syringe confirms you finished the Easter Egg.

Loot Drop and Mutant Injection Item — The final loot drop holds cash and the Mutant Injection device. Shown at 02:00 in Invoked by Red’s video. Image: Treyarch

Using the Mutant Injection to become a Mangler

Activating the Mutant Injection plays a short transformation animation and turns you into a Mangler for a limited time. The syringe gives you access to the same abilities the boss uses in Zombies.

Fire explosive blasts with the Mangler Cannon arm.
Melee nearby players with your sickle.
Charge through enemies with a sprint attack to down them.

Mangler Gameplay Showcase — As the Mangler, you can fire explosive arm blasts and charge through enemy players. Shown at 00:53 in Kokopelli’s video. Image: Treyarch

The transformation lasts only for a short period, so it works best as a burst of pressure during a fight rather than a full-match plan. Once the timer runs out, you return to your standard loadout and can carry on the match as normal.