The looping waterslide at Action Park.

Action Park was nicknamed “Traction Park”, “Accident Park”, “Class Action Park”, “Danger Park” and “Death Park” by doctors at nearby hospitals due to the number of severely injured parkgoers they treated.
Ride designers may have had insufficient training in physics or engineering. “They seemed to build rides,” one attendee recalls, “not knowing how they would work, and [then let] people on them.” (wikipedia)

I fondly remember attending Warped Tour here back in ‘96 and almost drowning after getting shot out of a high speed water-slide that ended with a 15 foot drop into a pool.
The park closed down for good at the end of that season.