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Biff punches and spray paints a camera, and later dumps a box of ping-pong balls on the floor, causing the IFT scientists to trip and bang into a wall (no blood).

Doc. Brown does a demonstration with a mini-delorean that catches on fire, and also dumps a glass pellet into a garbage can which explodes in a cloud of dust.

In the main ride part, the viewers crash through different signs, into a clocktower, and bang into ice blocks. Also, a dinosaur menacingly clenches his jaws at viewers.

The viewers also get caught in a lava slide.

Multiple uses of "butthead", but nothing more.

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The final part of the ride, where viewers feel as if they're caught in a lava slide, is fairly intense and may scare the youngest of viewers.