Simon and Marshalls Excellent Adventure (Eerie, Indiana)

Many of Marshall's possessions--his old sneakers, his homework, his just-finished model kit, the papers from his paper route, even the gum from under his desk at school--all start disappearing into thin air. He and Simon suspect a strange new kid at school, and set a trap. But the truth is more than even they have suspected: Marshall's stuff is headed for the future.