Slender Man—an urban legend that spawned a horror movie character and a video game—influenced two young Wisconsin girls to stab a classmate back in 2014. The next logical step, rather than embark on an educational campaign to teach children and teenagers about how to deal with internet memes and folklore, was obviously to turn the Slender Man craze into a movie. There’s even a creepy AF trailer for the horror movie, which is due out in theaters in May. But the father of one of the two girls who stabbed their classmate is now speaking out against the movie.

In 2014, two 12-year-old girls, Anissa Weier and Morgan Geyser, stabbed a classmate named Payton Leutner 19 times in a wooded park in order to “appease” Slender Man. According to the Washington Post, the girls told detectives they were “Slender Man’s servants” and had to “protect their families” from the fictional character.

Weier’s father, Bill Weier, has recently spoken out against the upcoming movie. He said Wednesday that the movie is in “extreme poor taste,” especially in light of what happened with his daughter. Weier also went further: local theaters shouldn’t show it.

Slender Man is a horror character created by the Something Awful user-written horror forum, but he shows up in various horror stories and games on the internet and often stalks and traumatizes people, especially children. Slender Man has been referenced in Minecraft and is the main subject of two video games entirely devoted to him: Slender: The Eight Pages and Slender: The Arrival.