Actress Mia Goth -- known for the films "X" and "Pearl" -- is being sued by a background extra of her upcoming film in the series ... after allegedly kicking him in the head on purpose during a take.
According to the docs, obtained by TMZ, Mia, director Ti West, and A24 are all being sued by an extra for the upcoming flick, claiming things got physical last year while they were shooting late at night.
The background actor says the scene called for him to wear a robe and be covered in fake blood from head to toe ... and he says he had to lay down in the dirt and play dead for several hours, "enduring ants and mosquitoes."
Mia, who plays Maxine, was supposed to run past the actor, step over him and look at him, then keep running ... but after a few takes, the actor claims Mia "nearly stepped" on him.
He says Mia was warned to be careful but instead, he claims she "intentionally kicked" him in the head with her boot on the following take, causing serious pain and neck stiffness. He says doctors later told him he suffered a concussion.
He claims no medical assistance was provided on set. Instead, he says Mia approached him in the bathroom and "taunted, mocked, and belittled" him ... daring them to do anything about what went down.
What's more, he says the fake blood had stuck to his body, so peeling off the blood-stained robe caused more pain -- and he claims he experienced headaches on the drive home and "nearly passed out twice" during the trip.
As if that wasn't enough, the actor says he was taken off the production following the incident. He's now suing for at least $500K in damages for battery and wrongful termination ... plus punitives. We've reached out to Mia's team for comment ... so far, no word back.