Yes, you can take a backpack on the Twilight Zone Tower of Terror at Disney's Hollywood Studios (or its counterparts in Paris and Tokyo). Unlike high-speed outdoor roller coasters with loops, the Tower of Terror is a "drop" ride that uses a vertical motion system where the elevator vehicle stays enclosed. There are no lockers required for this attraction. When you board the elevator, you simply place your backpack on the floor between your feet or in the small mesh storage pouch provided on the back of the seat in front of you (though most standard backpacks are too large for the pouch). It is recommended to loop one of the backpack straps around your leg or arm to ensure it doesn't "float" during the moments of weightlessness when the elevator drops faster than the speed of gravity. Because the ride features sudden vertical drops and "airtime," any loose items not secured could potentially hit you or other passengers, so ensuring your bag is zipped tight and tucked firmly under your legs is essential for both safety and preventing the loss of your belongings.