Xcalibur is an Evolution ride built by Ronald Bussink Professional Rides Evolution, one of only three of its type ever built. It resembles the "gyro swing" rides that are present at many other theme parks, but offers a very different ride experience.
Riders board cars that are arranged in a circle at the end of a long arm. These rotate in a circle, as the arm itself rotates 360 degrees. The cars are able to tip back, leaving riders lying on their backs.