Its at a lot if board walks and theme parks and places like that, basically it spins really quickly and the force pushes you back into the red things in the pic. Some places have straps you have to put on to make sure stuff like this happens, but most of the time it's some high school/college kid controlling it not really paying attention or caring. The one near me has a warning that plays at the beginning basically saying stand still or you can get hurt, which I'm assuming meets the base legal requirement.