Acid planet (The Halloween Apocalypse)

Karvanista left the Thirteenth Doctor and Yasmin Khan handcuffed and footlocked to a gravity bar above a boiling acid ocean on an unnamed planet.

Within four minutes, the entire planet was due to be engulfed by a nearby giant red star. Karvanista left his Kill Disks to ensure the Doctor's demise. (TV: The Halloween Apocalypse)