Dead Island 2

You won't find mutators until very late into the main story line. There is a mutator hot spot in "The Metro" and another in "Beverly Hills". The one in Beverly Hills is much easier as there are not as many zombies making it easier to sneak around.

To slay a mutator before it mutates you will need to find it laying on the ground and kill it very quickly before it starts to mutate.

I recommend trying this with a fully upgraded high power rifle or assault rifle. I did it with "Peggy" which is unlocked for completing a side mission with Curtiss in Bel Air.

If the mutator has already mutated quit to main menu and reload save to reset the area.

I found two spawn locations for the mutator shown in the video below.

Recommended gear: (You want to have as much crit damage as you can)
- Hunting Rifle (Preferably Peggy from the Curtis sidequests as it automatically comes with High Caliber. Mine has a Mutilator Mod, and the Damaging and Honed perks on it to maximize the damage when I ads with it)
- The Glass Cannon Numen card (If you play the main story, you should eventually get this, but I'm not 100% sure where it comes from)

To do this, the best place is to head to Rikky's house in Beverly Hills. His house is at the bottom right of the map, just down the street from Roxanne's house (where the fast travel map is). Mutators will start to have hot spots when you meet the first one during the main story, and Rikky's house will become a hotspot.

When you get to his house, use a melee weapon to kill any zombies that attack you, but otherwise keep your gun out. You're looking for an all-white, nearly naked-looking Walker (it has the title of Walker when it hasn't mutated), and it will be lying motionless on the ground, so if you don't alert it, it will be an easy kill. If you alert it and it mutates, just run out of the house and reload the game (return to the main menu, then continue the game) as it should put you somewhere close to the house and reset the Mutator.

NOTE: There can be a Crusher called The Bouncer that spawns here as well, so it might be best to kill them first then reload the map so they won't spawn again.

If you don’t have a hunting rifle, fury mode is also very useful on taking the mutator out in its walker form. Activating fury mode right next to the mutator will stun it and it should only take 2 strikes to kill it.

Another way that I’ve managed to pull off several times is to have a fully upgraded sledgehammer (Emma’s Wrath works best) and hit the mutator with a fully charged heavy attack. If you quickly run up to the mutator/walker it will take a swing at you instead of mutating so you’ll have time to take it out

After completing the game, zombie hotspots will appear on your map, making it easier to find mutators. To defeat a mutator before it transforms, you need a really strong gun to one shot them with. I recommend Peggy, a rifle earned through Curtis' side quests, which I fully modded focusing on damage. Then, find a mutator and maintain your distance to not alert them. Shoot it one in the head to hopefully one shot and defeat it easily.

Guaranteed Mutator.
When you first arrive at Hollywood Boulevard there will be a fuse box to open a train carriage, use it then use the nearby water jerrycan to complete the circuit on the ground. Move into the train carriage and kill the screamer on your right before it makes a sound. Next move along the train disarming traps as you go. Right at the end of the carriage, next to the lootbox, there will be a dormant walker sitting in a seat shoot him in the head with a good rifle and the achievement is yours.
The only reason I even noticed him is because I had my rifle out and my crosshairs went red, lucky me.

I used the blood rage weapon which is a knife I fount doing the lost and found I believe. I fount melee weapons better and got this in beverley hills. I also visited metro which is another good spot but DO NOT recommend it as its harder to get to. Any issues watch my Youtube tutorial to get it! -