The Interdimensional Fish Sticks (Locker 37, Bk. 4)

In the fourth book in the Locker 37 series, it's Halloween at Hopewell Elementary, but when fourth-grader Bryce Dodd shows up in a costume, he's told it's too distracting. All Bryce wants to do is express himself (and maybe also to impress Keisha James...), and luckily, the magical Locker 37 has a solution to Bryce's costume conundrum - interdimensional fish sticks! Each time he eats one, he's transported to a different parallel universe, and each time he travels to a new one, things get weird, weirder, to off-the-walls weird. Will Bryce be able to make it back to his home dimension and Keisha, or will he be stuck in an alternate universe forever?