Rules TextInstead of moving, roll a die. On a 4-6, all investigators in Arkham lose 1 Stamina.
Chthonians are huge worm like monsters that live under the ground and create violent earthquakes. Instead of moving, this monster is causing an earthquake across Arkham to damage the investigators. As a result, investigators in an Other World are not affected.
The Chthonians first appeared in Cement Surroundings (1969), written by Brian Lumley.