IT Chapter Two features a cameo from none other than IT author Stephen King himself. It's not the first time that the writer has appeared in an adaptation of one of his works; King played a minister delivering a eulogy in 1989's Pet Sematary, a pharmacist in the 1996 adaptation of Thinner, and more recently played a diner patron in the TV series Under the Dome. But while some of his appearances on screen have been fleeting, King gets to steal the scene in IT Chapter Two.
The sequel to 2017's IT, once again directed by Andy Muschietti, IT Chapter Two picks up 27 years later, with the Losers' Club now adults who have grown apart and forgotten their childhood experiences in Derry. When Pennywise returns to claim new victims, however, Mike Hanlon calls everyone back to Derry to recover their lost memories and put an end to the evil clown once and for all. Before he's ready to head out and find the token that he needs for the Ritual of Chüd, Bill Denbrough (played as an adult by James McAvoy) makes a pit stop at Derry's local pawn shop after noticing his old bike, Silver, in the window.
It's when Bill enters that pawn shop with plans to buy his old bike that King makes his cameo, as the pawn shop's surly owner - and it's here that he has a little bit of fun at his own expense. King is known for writing books that feature writers as the protagonist, and in IT Bill grows up to be an author of thriller and horror novels, effectively serving as King's self-insert character. In IT Chapter Two there's a running joke that while Bill is a very successful writer, he can't write a good ending to save his life. So, when Bill notices one of his novels on the shop counter and offers to sign it, King's character declines, saying that he didn't like the ending. He also charges the rip-off sum of $300 for Bill's rickety old bike, on the grounds that Bill is rich enough to afford it. Bill doesn't mind, however, telling King that Silver was "fast enough to beat the devil."
Screenwriter Gary Dauberman doesn't actually think that King's endings are bad, but instead wrote the running gag into IT Chapter Two in response to fierce internet debates about the quality of King's endings. “I think he has stuck the landing over and over again on many of his stories. The proof is in the pudding on that," Dauberman told Inverse. He also explained that he originally "wrote him into the script just along the lines of, 'Looks like Stephen King,' early on in the drafts. You know, just kind of planting the seed."
Fortunately Muschietti had developed a good relationship with King after the success of IT, and was able to convince him to do his first movie cameo in a long time. Speaking to GamesRadar, Muschietti said that upon being asked to cameo, King joked, "You have to know I’m a jinx. Every movie I was in bombed." With a $92 million opening weekend, however, it looks like IT Chapter Two has broken the box office curse.