Based on the R.L. Stine series of books, Goosebumps 2: Haunted Halloween is the sequel to Goosebumps from 2015. The premise of the series is when the books are opened, the characters from the horror stories are able to escape into the real world.
In Goosebumps 2: Haunted Halloween two boys named Sonny and Sam find a manuscript labeled “Haunted Halloween” in an abandoned house that was previously owned by R. L. Stine. They unwittingly release Slappy by opening the manuscript. Slappy has plans to create the Halloween Apocalypse with the help of his Halloween monster allies. Of course, Sonny and Sam with help from Sonny’s sister, Sarah, must stop Slappy’s plot and return him to the manuscript.