Sphere of Crushing Doom

Generic Hazard

The court jester devised a deadly trap to foil anyone who sought to steal his magic fool’s cap. The jester’s tomb is located at the end of a 10-foot-wide, 150-foot-long hallway that descends sharply from north to south. The entrance to the tomb is a door on the eastern wall at the bottom of the slope, at the south end of the hall.

Source: Xanathar’s Guide to Everything p. 119