Dr. Diabolical’s Cliffhanger, Dive coaster in Crackaxle Canyon, Six Flags Fiesta Texas, San Antonio, US.

Dr. Diabolical's Cliffhanger is a steel dive coaster at Six Flags Fiesta Texas in San Antonio, built by Bolliger & Mabillard. Its 150-foot lift hill climbs between tall yellow columns, and the red track with pale gray rails turns through a wide flat spine before a 95-degree drop. The 2,501-foot layout also has a 75-foot near-vertical drop, an Immelmann, a zero-g roll and a 360-degree helix.

The ride was built on the location of an entertainment venue that had operated since 1992 and opened in 2022. Its arrival marked the park's 30th anniversary celebration with a major new addition.

The ride incorporates a narrative about Dr. Diabolical, who uses a machine to collect human adrenaline and fear to create various creatures.

Guests need to fall within a specific height range to board, roughly between 4 feet and 6 feet 6 inches tall. Waits tend to build throughout the afternoon, so early morning visits often mean shorter lines and more comfort.

It was the first Bolliger & Mabillard coaster with a drop beyond 90 degrees, and from 2022 to 2025 it held the steepest-drop record for the Dive Coaster model before Wrath of Rakshasa surpassed it. The ride was first planned for Six Flags Great America in Illinois, which chose a larger Dive Coaster instead.