Goosebumps 2: Haunted Halloween

Teenager Sarah Quinn lives with her mother, Kathy, and her teenage brother, Sonny, in the New York town of Wardenclyffe and is writing an essay for her college application as Halloween is just around the corner. Sonny's friend, Sam Carter, is dropped off at their house to be looked after while his parents are away for the next three days.
Scavenging for items in an abandoned house formerly owned by R. L. Stine after school, they find an unpublished Goosebumps manuscript and unlock it, resulting in Slappy the Dummy appearing, who is currently inanimate. Leaving the house after obliviously reading the incantation that brings Slappy to life, they are intercepted by bully Tommy Madigan, who steals the manuscript from them. He and his friends attempt to chase the duo home, but are secretly stopped by the now-brought-to-life Slappy.
Back home, Slappy reveals his sentience to the duo, but requests them to keep him a secret from the other Quinns. Over the next few days, Slappy tries to assert himself as a member of the family by assaulting Sarah’s ex-boyfriend, Tyler Mitchell, for recently cheating on her and causing damage to one of the classrooms of Sonny’s school after sabotaging his science project, a working model of the abandoned Wardenclyffe Tower created by Nikola Tesla. Now aware of Slappy’s true nature, the duo and Sarah settle on getting rid of him, only for him to escape when they attempt to do so.
Halloween night arrives and while Mr. Chu hands out candy to trick-or-treaters, the kids find an article online regarding events that occurred in the Delawarean town of Madison.[a] Through some more research, they realize that the unpublished manuscript is required to stop Slappy. They then attempt to contact R. L. Stine for help, but leave a voicemail when he is unavailable. Meanwhile, Slappy visits a local Fred's and uses his powers to bring various Halloween costumes and decorations to life, some of which are Goosebumps themed, as well as brainwashing the store’s manager, Walter, to his cause using a mask.
Slappy soon reactivates the Wardenclyffe Tower and uses it to bring the town’s Halloween decor to life. As Sonny and Sam retrieve the manuscript at Tommy’s house, during which they discover it can be used to imprison anything Slappy had brought to life, it is unfortunately stolen by his forces as they then abduct Kathy. Mr. Chu, the Quinns' neighbor and an avid Goosebumps fan, assists the duo and Sarah in disguising themselves to safely navigate the town.
They infiltrate the Wardenclyffe Tower and confront Slappy, who has now made Kathy like him. After some conflict, the trio defeat Slappy as Sarah combines the recovered manuscript's power with the energy of the tower’s reactor to save the town, with Kathy and Walter being returned to normal. In the aftermath, Stine arrives at the tower, having received the trio’s voicemail only to learn that the threat has been neutralized and congratulates them for their heroism, as well as giving Sarah advice on writing her essay.
Afterwards, Kathy and Walter begin dating and Sarah is accepted after completing her application. Elsewhere, Stine is confronted by a surviving Slappy, who entraps his creator in a new Goosebumps story he himself conceived.