Xcalibur was a spinning thrill ride located in Britannia at Six Flags St. Louis in Eureka, Missouri.

Xcalibur was announced at Six Flags Great Adventure as Evolution, for the 1999 season along with 24 other attractions, known as War on Lines.

[2] Evolution was relocated to Six Flags St. Louis and opened at the Missouri park in Spring 2003 as Xcalibur.

[1] During the relocation Xcalibur received a better control panel than before and enhanced Medieval theme elements.

Xcalibur's speed and direction was determined by servos located in the hub of the ride at the top of the leg supports.