Prepare to get turned upside down if you visit Six Flags St. Louis, with Xcalibur, a new spinning-type ride guaranteed to dizzy and disorient. Designed and created by manufacturer Nauta Bussink Baily, Xcalibur lands at the Eureka, Missouri-based theme park as the latest addition to the park's arsenal in the extreme ride war, joining a collection of thrill rides already including the inverted, looping Batman: the Ride; launched, shuttle-looper Mr. Freeze; and the wooden terrain coaster Boss. The 2003 thrill ride originated at New Jersey's Six Flags outpost, Six Flags Great Adventure, where it operated since 1999 as Evolution, being given the medieval Xcalibur theme at its new location and opening to a whole new region of thrill seekers. The ride's 56-foot-long arm tosses and turns up to sixty-four passengers per cycle up to 113 feet above the Missouri turf during a ride of two minutes, swinging back and forth and gradually gaining altitude as it goes. Seated around an inwards-facing, multicolored circular arrangement, the ride rotates sixteen free-swinging groups of four thrill riders simultaneously for another two axes of action to help create the disorienting ride experience.

When at Six Flags Great Adventure under the name of Evolution, the ride was prone to problems with the complicated control panel, which only a couple employees at the park could operate. Since opening at St. Louis, the control panel was improved to be more user-friendly and given the Medieval theme of Xcaliber.

Journeying back into Six Flags St. Louis, ride conquerors ready to take on Xcalibur, minimum fifty-four inches in height, can enter the line and prepare to board. The maximum of sixty-four passengers are arranged in the ring of sixteen cars of four riders and held into the sit-down position by over-the-shoulder restraints. The ride starts up with tri-axes spinning and swinging motion, the ring of passengers slowly rotating in circles as the main arm swings higher into the air. At the top 113-foot elevation, riders on Xcalibur find themselves completely inverted, suspended heads-first eleven stories over the park while the seating continues to spin in full three-sixty rotations. The ride pauses briefly in the vertical position just long enough to serve up some 'hang' time and give an appreciable view from the inverted perspective. Finally, the quest starts back down again and swings back to terra-firma for riders to unload.