The doom sphere is made of black force energy and has spikes of force protruding in every direction. It appears on the north side of the inner track, the corridor surrounding the central chamber, and begins moving.

Trap: The doom sphere is the size of a Large creature. Each round, it moves clockwise, traveling in an endless circuit around the inner track.

Initiative: +9

Speed: 12

Trigger

When the four items are placed in the runic circles, the trap rolls initiative. The doom sphere double moves on its turn, moving through squares occupied by creatures. It attacks every creature whose space it enters.

Attack

Move Action - Melee
Target: Every creature whose space the doom sphere enters.
Attack: +8 vs. Ref
Hit: 3d6 + 5 damage, and the doom sphere makes a secondary attack against the same target.

Secondary Attack

Attack: +8 vs. Fort
Hit: The target is knocked prone. If the doom sphere ends its movement in a creature’s space, that creature slides to the nearest unoccupied space.