X2 (originally X) is a groundbreaking steel roller coaster at Six Flags Magic Mountain in Valencia, California, that opened on January 12, 2002, as the world's first fourth-dimension coaster and the final ride from Arrow Dynamics. Its unique feature is that each seat pitches 360 degrees forward and backward independently of the main chassis, a concept imagined by designer Alan Schilke and pushed to hyper-coaster scale by park president Gary Story. The ride faced a troubled debut, including design flaws, Arrow Dynamics' bankruptcy, and a closure in June 2002 for train issues before reopening in August. After a $10 million redesign, it reopened on May 24, 2008, as X2, featuring new lighter trains, a red-and-black paint scheme, and special effects like onboard audio, fog, and flame throwers. However, the ride has been closed since July 12, 2026, following an incident where two riders suffered brain hemorrhages, leaving one in a coma as of late August 2026.