Last night, Firaxis unveiled Red Death, an honest-to-god battle royale mode for Civilization 6. And if you think that sounds like a weird joke, that’s because it sort of is – Red Death began life as a literal April Fools’ joke.

Discussing the new mode last night on Reddit, one fan said “I literally did a double take wondering if it was April 1st already.” In response, marketing manager Kevin Schultz told them that it was “funny you should say that. [Red Death] did start off as an internal April Fools joke before everyone on the team collectively went ‘huh…this is really fun’.”

In a press release, Firaxis confirmed that was the case, saying that “the game mode began as a tongue-in-cheek April Fools joke from the multiplayer engineering lead, Bradley Olson.” Olson snuck the mode into the basic gameplay ahead of April 1, but no-one noticed until he came clean during a meeting. Once the design team cottoned on, they set up an official play session later that day.

While the mode has changed significantly over the last few months (you can get a look at it in the trailer below), its origins were much less ambitious. “The original implementation was simple and straight-forward: each player had a Warrior unit and a Settler unit. You could earn new units from friendly villages (we call them “goody huts”). There was a ring of death that slowly collapsed in towards the center, and the last player with a surviving Settler won.”

That’s pretty standard battle royale, but it clearly stuck for the dev team: “we ended up having so much fin playing the mode that the design started to rapidly expand. Additional units went in and then more and more features started to come into the basic design.”

Red Death isn’t the first battle royale game to show up quite this unexpectedly, nor the first to appear as an April Fools tie-in. It is arguably, however, the weirdest joke mode I’ve ever seen introduced, particularly in the ‘historical 4X game’ category, so despite the devs’ enthusiasm, I’ll be interested to see what the players think.