'It: Chapter 2' bloodies Jessica Chastain in horrific new trailer at Comic-Con

SAN DIEGO – The first “It” introduced a freaky new take on demonic clown Pennywise and the Losers’ Club of kids who had to take him down, and a Comic-Con event Thursday night teased the sequel being quite a bit of bloody terrifying business, too.

Hosted by Conan O’Brien, Warner Bros’ annual “ScareDiego” presentation debuted the new trailer and three creepy scenes from “It: Chapter Two” (in theaters Sept. 6).

The follow-up to the hit 2017 Stephen King adaptation – the highest-grossing horror film of all time – catches up with the young “It” characters 27 years later as grownups (played by Bill Hader, James McAvoy, Jessica Chastain, Isaiah Mustafa, James Ransone, Jay Ryan and Andy Bean) who return to Derry, Maine, for one last showdown with Pennywise (Bill Skarsgard).

The first film “is a movie about friendship and the power of unity,” said director Andy Muschietti. “The second part is about trauma.”

That and a whole lot of fake blood – 4,500 gallons worth, in fact, according to Chastain. She would know since she spent quite a bit of filming covered in it.

In one key scene, Muschietti told Chastain she’d be covered in blood up to her collarbone but wouldn’t get in her face. “I was like, ‘No, if we’re going to do it, let’s do it. I love horror films, I love ‘Carrie,’ and I said, ‘Let’s make ‘Carrie’ on steroids,” Chastain said.

“And that’s what we did and it literally tortured me because I didn’t realize that it would be that way the whole movie.”

Filming scenes from that moment on, before every take Chastain would have to sit “in a kiddie pool filled with blood,” with people pouring buckets of it on her while a wind turbine kept it cold.

McAvoy explained that because there’s sugar in the fake blood, “if you heat it up, it ferments and goes putrid and it smells like puke.”

Chastain copped to being “probably very irritable” when freezing. “I’d get on set and be like, 'Please please shoot!'” Not that it was all serious: “I would make jokes of it and make slow-motion videos of me pouring blood all over my body.”

“I’d like to see those,” O’Brien quipped. He also compared himself to Pennywise: “I’m very pale and I frighten children.”

Hader, whose first King novel was “Salem’s Lot,” praised Skarsgard’s frightening villain and the way he could become “a whole other being.” He also recalled Skarsgard photobombing him on set with a Pennywise grin when FaceTiming with his kids. “Bill came up behind me,” Hader said, “and my daughter went, ‘What was that?!’“

McAvoy admitted he had strange nightmares about Pennywise when making the movie.

“The only one I can remember was I’m lying on my side in bed and he was in bed with me. He stroked my back and then said, ‘Wake up, James, wake up.’ I was just terrified and I thought, ‘I’ve got to pretend to be asleep.’ We’ve all been there.”

Chastain and others responded at the same time, “No, we haven’t!”

This article originally appeared on USA TODAY: 'It: Chapter 2' trailer bloodies up Jessica Chastain at Comic-Con