The guy behind one of the scariest clowns in history, Bill Skarsgard, showed off the crazy smile he did in the movie for Conan O’Brien — without makeup! And trust, it’s just as scary as you think…

Apparently, he came up with the scary smile for Pennywise the Clown years ago, when he was trying to scare his little brother. Turns out, scaring your siblings came in handy!

“My older brother Gustaf, who’s an actor as well, he had this ability to do, you know, point his lip in a very strange way and for some reason, I don’t know how, I understood that I could do it as well.”

Check it out above.