Pennywise Wasn’t the Only Thing That Terrified the 'IT' Cast on Set

In Stephen King's IT, a monstrous entity takes many shapes and forms to terrify a group of kids, most famously embodying Pennywise the clown. While actor Bill Skarsgard in his full clown makeup was a scary sight to behold, the cast revealed that mice became more startling on set than Pennywise himself.

During a recent interview, the young stars discussed that the interior sets of a dilapidated house on the fictional Neibolt Street were terrifyingly convincing, thanks to some furry critters. Of filming those sequences, Finn Wolfhard revealed, "I was scared. They ran across our feet and I was actually scared."

Chosen Jacobs was both surprised and impressed with his animal co-stars, explaining, "The craziest thing that I saw, they have trained mice, because the Neibolt house, they had mice running through. I never knew people trained mice to do things in movies."

Capturing the atmosphere of a run-down house was integral to the scenes, with the building playing an integral role in the narrative.

In the novel, Eddie Kaspbrak first sees the monstrous "It" emerging from the abandoned house's basement, alternating between appearing as a leperous transient and as Pennywise the clown. After telling the rest of the Losers' Club about this encounter, they decide that this could potentially be the monster's lair, returning to confront It once and for all. From there, the Losers' Club follows the being into the nearby sewer, which is where they have their first confrontation with Pennywise.

When the Losers' Club become adults, a body is discovered near the decrepit house, which tips the friends off to the idea that Pennywise has possibly returned.

The film's director, Andy Muschietti, didn't necessarily discourage the young cast from interacting with Skarsgard as Pennywise, but intentionally delayed their introduction as to capture the horror of his appearance.

"We wanted to carry the impact of the encounters to when the cameras were rolling," Muschietti detailed to Variety. "The first scene where Bill interacted with the children, it was fun to see how the plan worked. The kids were really, really creeped out by Bill. He's pretty intimidating because he's six-four and has all this makeup."

IT is now in theaters.