Bill Skarsgård brought a lot to the role of the demonic Pennywise the Dancing Clown in director Andy Muschietti's It. Madness? Of course. Unpredictability? You betcha. An unsettling baby voice? Yep! But it was Skarsgård's physicality — especially his facial expressions, often dripping with saliva — that really elevated Pennywise from a scary clown to full-fledged nightmare fuel.

Case in point: the creature's haunting smile. As it turns out, that smile was not the result of special effects makeup. That was all Skarsgård. In fact, it was inspired by a character he created as a child to terrorize his younger brother Valter. Of course, that means he can still make THE FACE on command. I, for one, was not prepared.

"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," the actor told host Conan O'Brien during Tuesday night's episode of Conan. So, he'd pull his t-shirt over his head, make the face, and chase after his baby brother. How cute.

It's a little unsettling how easily he can transform his beautiful face, but I guess it's the ultimate party trick. Anyway, this is the face you see before you die:

"He brought madness to the character," Muschietti told MTV News at a press day for It last month. "He brought unpredictability. These are two traits of the character that I wanted to bring to this version."

Watch more our interview with Muschietti and the young cast of It in the video below.