Attack of the Jack / I Am Slappy's Evil Twin(2017)

R.L. Stine

Devin and his sister Violet are visiting their Uncle Jack for the summer. He lives in an old house by the seashore. Jack was a sailor and he has collected strange and fascinating items from the sea. Exploring a back room, Devin and Violet discover a locked trunk. A pirate's chest.
Luke Harrison's dad makes horror movies. It's very fun to be around such scary stuff-especially when you have your own monster museum at home. But when two ventriloquist dummies join the collection, things get real creepy. Real-life creepy Slappy and Snappy can walk and talk on their own. And they can make you scream on their own. They have a plan to make everyone's lives miserable. Will Luke be able to stop this terrible twin twosome?