"Slappy in Dreamland" is indeed a book by R.L. Stine. It is part of the "Goosebumps SlappyWorld" series and was published in 2022. The story follows a boy named Richard Hsieh, whose dreams become increasingly terrifying after his new Slappy doll is hooked up to his dad's dream machine as a prank. As with many of R.L. Stine's books, "Slappy in Dreamland" combines elements of horror, suspense, and humor to create a thrilling and entertaining reading experience. It is a popular choice among young readers who enjoy spooky and funny stories.