Game of Thrones is filming its eighth and final season, but luckily there’s another place you’ll soon be able to catch Maisie Williams (aka Arya Stark) on screen. The actress stars in Marvel’s The New Mutants, a spinoff that takes places within the X-Men universe, and the first trailer will seriously give you nightmares.

Williams isn’t the only recognizable face in the film: Stranger Things breakout star Charlie Heaton plays one of Williams’s fellow mutants, and we’re fangirling over the collision of these two beloved worlds. Williams and Heaton star alongside 13 Reasons Why’s Henry Zaga, The Originals’s Blu Hunt, and The Witch’s Anya Taylor-Joy as young mutants who are being kept in a secret facility by some sketchy scientists.

“We are making a full-fledged horror movie set within the X-Men universe,” director Josh Boone told EW. “There are no costumes. There are no supervillians. We’re trying to do something very, very different.”

Seeing as this trailer had me terrified, I think they succeeded.

BTW, Williams isn’t the only Game of Thrones star to cross over into the X-Men world. Her BFF Sophie Turner (Sansa Stark) first starred as Jean Gray in X-Men: Apocalypse and she’ll reprise her role in 2018’s X-Men: Dark Phoenix.

The New Mutants hits theaters April 13, 2018. Watch the new trailer at top.