In the grass ahead lurks a cotton-ball puff of a creature with stubby appendages, round, yellow eyes, and a macaroni-noodle smile. Appropriately named Lamball, it is one of many island creatures that can become your pal, with the right touch: smashing it over the head with a big wooden stick (to weaken it, of course), then trapping it in a Pal Sphere, a colorful ball that will act as the creature’s new home.

Does that sound familiar? It’s the same formula (minus the battery) the creators of Pokémon built an empire on. It’s no surprise, then, that people have been calling Palworld “Pokémon with guns” pretty much since it was announced in 2021. On January 19, the game launched on Steam Early Access and Xbox Game Pass. In just a few days, the game has quite literally achieved overnight success for little-known developer Pocket Pair: 5 million copies sold, according to its creators, since its release. It’s a chart-topper on Steam, with more than 1.5 million concurrent players as of this writing, as well as on Twitch, racking up more than 340,000 viewers on PalWorld streams since its launch. It’s been so popular that the game’s servers have been struggling to keep up.

Despite the nickname, Palworld is more open-world survival game than a traditional creature collector. One where you’re better off if you eat your cute little friends when no other food is readily available. You’ll need to build a base camp, start fires to keep warm and, eventually, equip your pals with guns to stay alive. The premise has been so outlandish for some that, ahead of the game’s launch, Pocket Pair felt the need to confirm “it is not a scam and will definitely be released.”

If you’re wondering why it’s so popular, you’re not alone. On Reddit, users have offered a variety of explanations pointing to a perfect storm: the allure of a survival game like Rust, paired with the cute pet-like nature of Pokémon; the desire from traditional Pokémon players for more open-world games; the utterly bizarre nature of Palworld itself. “You know when you’re scrolling on a website and you see an absolutely insane ad for a game and it’s like “C[L]ICK HERE TO PLAY NOW!!l” and you know it’s a scam,” wrote one user. “Well this game is like those ads, but real. It’s absolutely nuts.”

The game’s success is not without complications. On X, users continue to share photos of Palworld characters who bear striking similarities to various pokémon. In an interview with Automaton, Pocket Pair CEO Takuro Mizobe said the company takes its games “very seriously, and we have absolutely no intention of infringing upon the intellectual property of other companies.” (Nintendo, which publishes the Pokémon video games, did not immediately respond to an email seeking comment on this story.)

That hasn’t stopped players from modding Pokémon into the game, giving pickaxes to Pikachus and putting a bow and arrow in the hands of Ash Ketchum. It’s not exactly Petilil with a pistol, but it’s pretty close, and it brings the darkly funny allure of Palworld to the fore.