Nintendo posts new trailers for upcoming Switch games all the time on its YouTube channel, but not like this. On Wednesday morning, the company uploaded a teaser titled “Emio” that’s only fifteen seconds long, stars a person with a creepy paper bag over their head, and appears to tease an unannounced horror game coming to the handheld hybrid sometime in the future.

The new trailer was announced on social media by the Nintendo of America account, with a tweet that simply read “#WhoIsEmio?” and a link to the YouTube page. That was the first sign that something unusual was going on. The second was that the page was age-restricted, a rare move for the family-friendly gaming company. Here’s a look at the trailer itself:

A child’s piano plays a few creepy notes. A person in a trench coat wearing a bag over their head with a smiling Jack-o’-lantern cutout pops into the frame. You can see their shadow cast against a wall that appears to be made of cardboard, with a piece of duck tape running down the middle. The camera suddenly cuts to the person’s hand which appears to be missing a finger. It then cuts to a close-up of their face before cutting back to a shot of a person wearing a different paper bag with a Cheshire cat grin on it. According to fan translations, the Japanese characters that appear at the end say “smiling man.”

Responses in the comments on Twitter have been all over the place, with some players going “wtf?”, others joking that Nintendo had finally caught a recent well-known video game leaker. Some are wondering if this is a sign that Nintendo is making a first-party horror IP from the ground-up. The teaser shows all the signs of an attempted viral alternate reality game (ARG) for a potential analog-style creep-fest.

Nintendo’s mission statement is to “put smiles on the faces of everyone we touch.” Emio gives that wholesome motto a new sinister twist.