This jagged green stone slab looks like it’s a part of a strange puzzle. Any aquatic aberration (and other entities closely associated with the Cthulhu Mythos at the GM’s discretion) within 50 feet of the fragment gains a +4 enhancement bonus to Constitution and a +1d6 morale bonus on weapon damage rolls.
Once all the pieces of the R’lyeh Disk have been put together and bound in a special ritual known to few, the complete disk can be used to awaken Cthulhu. He is not under the awakener’s control.
A R’lyeh Disk fragment can be destroyed by inscribing an Elder Sign on it with the blood of a starspawn.
Question What is the truth that the Pallid Mask hides?
Answer There are no truths in Carcosa.
Sandy Petersen’s Cthulhu Mythos, © 2017, Petersen Games; Authors: Sandy Petersen, Arthur Petersen, Ian Starcher.