Slashers

You may be looking for the Slashers Events or the Los Santos Slasher.

“Like any good horror movie, this isn't supposed to be fair. You're supposed to be fleeing in terror with only a flashlight for company, pursued by a crew of deranged, shotgun-wielding psychos. Your only consolation is that in less than a minute, the roles are going to switch, and it's you who'll be drenched in the cold blood of your enemies. Last team standing wins.”

—In-game description.

Slashers^[1] is an Adversary Mode featured in Grand Theft Auto Online as part of the continuation of The Doomsday Heist update, released on December 26, 2017, during the Festive Surprise 2017 event.

Description

“The anxiety-inducing fun of classic Adversary Mode Slasher is back with a vengeance… plus an extra letter. Introducing Slashers - a terrifying ordeal that pits two teams against one another, each desperately scrambling to outlive the opposition. The Slashers, armed with Machetes and Shotguns, must wade through the darkness in pursuit of the Hunted, who are equipped with Thermal Vision and Flashlights. But don't get too comfortable - as each minute passes, the team roles are reversed until one group has been wiped out completely.”

—Rockstar Newswire description.

The players are divided into two teams - the Slashers and the Hunted. This Adversary Mode works in a similar fashion to the original Slasher mode, except that there are now more than one Slashers.

When the round starts, the Slashers team has to hunt down the Hunted. Each round takes five minutes, and every minute, the teams are swapped.

As with the original game mode, these missions focus on darkness, and they take place inside various buildings. The Slashers team is given shotguns with flashlights, while the Hunted team is given a flashlight. Unlike the original mode, however, the Hunted are also given thermal vision googles.

The team that takes out the entire enemy's team wins the round.

Locations

There are seven Slashers missions in GTA Online, each taking place in a different location, which are as follows:

Image	Location	Map
	Slashers I takes place inside the server farm from Setup: Server Farm.
	Slashers II takes place at the area inside the missile base where players must destroy supply crates in The Doomsday Scenario.
	Slashers III takes place inside the IAA base on the Satellite Relay Station.
	Slashers IV takes place at the area inside the missile base where players must hack the terminals in The Doomsday Scenario.
	Slashers V takes place inside the hangar from Setup: Avenger.
	Slashers VI takes place on the USS Luxington ATT-16.
	Slashers VII takes place inside Humane Labs and Research.