Forget about stealing from El Rubio, the leaked update will have you fighting for your life against hordes of the undead.

According to recent datamining discoveries, the entire Cayo Perico island is about to become ground zero for an undead apocalypse.

Halloween in Grand Theft Auto Online has become something of a tradition for longtime players. Last year, in particular, was huge for the game. However, this year, Rockstar Games appears to be pulling out all the stops.

A new zombie survival mode, apparently hidden within the recent Money Fronts update files, transforms the familiar Cayo Perico island into a multi-stage nightmare.

The mode starts you off at the compound, that heavily fortified area we've all infiltrated dozens of times. But instead of sneaking past guards, you'll be mowing down zombies as you fight your way to the outside.

Dataminers have identified at least four distinct zombie variants, including something called a "Splitter" and "The Conquistador". The latter is a skeletal enemy that's reportedly immune to both explosives and regular bullets.

The only way to take down The Conquistador? A well-placed headshot that literally knocks its skull clean off.

Once you've survived all four locations, you can either make a dramatic escape by racing to the airstrip and piloting a Velum back to Los Santos (while being chased by zombies, naturally), or you can choose to stay and face endless waves at any of the four locations you've already cleared.

Even for veteran Grand Theft Auto, this new mode represents a first. It's a full journey across an entire island with multiple stages, unique enemies, and actual strategic choices to make.

The best part? All of this content is already in the game files. So, come October, we'll all head back to Cayo Perico, but instead of leaving with bags of gold, we'll be lucky to leave with our lives.

In the meantime, GTA Online players can check out the latest update and nab some freebies, especially if they're subscribed to GTA+.