The chilling conclusion of Episode 5 in IT: Welcome to Derry is guaranteed to unsettle even the most devoted Stephen King enthusiasts. While the episode already thrills with the protagonists’ exploration of the infamous Neibolt Street house and the dramatic unveiling of Pennywise, portrayed by Bill Skarsgård, the real horror lies elsewhere. It centers on Dick Hallorann, played by Chris Chalk, and the dark secrets concealed in his mysterious “lockbox.”

**Spoilers for IT: Welcome to Derry Episode 5, currently available on HBO Max**

The episode reaches its climax with Dick Hallorann emerging from the sewers, having been bested by Pennywise in a psychic confrontation. This battle dredges up the haunting past of the character from The Shining and Doctor Sleep, revealing his most buried fears.

In a disturbing vision, Dick finds himself shackled in his childhood bathroom, where his grandmother, portrayed by Lazzelle Gelias, tries to offer guidance. She ominously warns him, “he’s coming for you again.” Adding to the tension, Dick’s menacing grandfather, played by Andrew Moodie, appears clutching a gun and a locked box.

The grandfather mocks Dick, belittling his wife’s advice to seal away negative emotions within the lockbox, suggesting instead that such power should be unleashed. Despite Dick’s desperate attempts to resist, his grandfather—revealed to be Pennywise in disguise—compels him to confront the horrors hidden inside.

When Dick finally emerges from the sewers, he not only appears shellshocked, but can see a zombie-version of Captain Pauly Russo (Rudy Mancuso). Pauly has just died saving Will Hanlon (Blake Cameron James).

So what is all this? What was in Dick Hallorann’s box? What does this latest development have to do with lore Stephen King introduced in The Shining‘s sequel, Doctor Sleep? Here’s what you need to know about the end of IT: Welcome to Derry Episode 5…

IT: Welcome to Derry Episode 5 Ending Explained: What is in Dick Hallorann’s “Lockbox”? How Is it Connected to Doctor Sleep?

First thing’s first: What exactly is Dick Hallorann’s box? Well, it’s a concept introduced in Stephen King’s Doctor Sleep in a scene where the older Dick Hallorann (Carl Lumbly) teaches young Danny Torrance (Roger Dale Floyd) how to lock all of his negative psychic memories and experiences in a box.

IT: Welcome to Derry‘s own Dick Hallorann, Chris Chalk, described it to DECIDER this way: “Okay, think of this: If you had the ability to see beyond this reality since you were a wee one and you were told, ‘Put it in a box.’ So imagine all of the things we hate about ourselves, or we hate about the people across us, and we just put it down. We just stuff it, we stuff it. It’s really that.”

“All the terror that he has ever seen, he just slipped it in the box, slipped it in the box, slipped it in the box,” Chalk continued. “So the moment you unleash that, it’s not going to come out as gently as Dick put it in and it’s not happy about being shoved in a box. These are not entities that want to be trapped. And so when they can break free, they do and it changes Dick forever.”

Opening the box doesn’t just change Dick, though. IT: Welcome to Derry executive producer and co-showrunner Jason Fuchs told DECIDER, “The box is very much open and it’s not easy to close.”

“That very last shot you see of Dick, of Chris Chalk, in [Episode] 5 of him seeing dead Pauly in front of him on the bank of the river, that is going to take Dick to some extremely dark places, to a place he’s tried to get away from,” Fuchs said. “There’s a reason he wanted to keep that box shut. His life by the end of Episode 5 has been fully upended in ways that will take him to the breaking point and possibly past in the episodes to come.” 

When DECIDER caught up with Captain Pauly Russo himself, Rudy Mancuso, he teased that while we’re not going to see much more of his character, even in zombie/spirit form, we are going to continue to see some gnarly stuff emerging from Dick’s box.

“I definitely know that we’re going to see more,” Mancuso said. “We’re going to dive a little bit deeper into that type of, not necessarily Pauly, but the type of entity that he’s representing.”

Mancuso also revealed that it wasn’t necessarily hard for him to capture Pauly’s eerie energy.

“That day was was strange because we’re fighting against time, as we always do. I had fucking contacts in my eyes. I couldn’t see anything. And I was in the woods. It’s almost like releasing a rabid animal into the woods,” Mancuso said. “I was confused. Equally confused in real life as Pauly was this supernatural state.”

What terrifying specters will emerge from Dick Hallorann’s box next? We’ll have to watch IT: Welcome to Derry Episode 6 next Sunday night to find out…