Give Yourself Goosebumps Book 34 Elevator To Nowhere

Uncle Darius is an inventor. Right now he's testing out his transuniversal Transvator. It looks like an elevator but it takes passengers to other universes! Uncle Darius says he'll prove it by bringing back a special souvenir, a shrunken head, but when Uncle Darius returns, something is wrong. How wrong? He wants to shrink your head and your only means of escape is battling his headhunter on earth or battling the unknown in the other universe. Hurry, the doors are closing!