Glass Bone is a very hard to find “substance” (or what constitutes as such) that can be taken from the Great Dream and has the property of “absorbing” strong emotional states.

The Halloween Party found a crate of these in the Cortijo de la Vara, where they had been acquired by a wealthy spanish occultist and were most probably the cause of his, his family's and his servant's death.

One was used by the Bowler-Hatted Man to actualize a Manifestation of Oblivion from the Great Dream, by telling a short story about some kind of eldritch deity.

The Bowler-Hatted Man said that these bones are the remains of almost forgotten dreams and memories leached of substance, meaning, and color, and they can only be found in a desert of broken glass in the deepest reaches of the Great Dream.

During Session 23, the main party found the remains of the forgotten goddess that became one with Claire Dubois. By grabbing one of these, Claire made the goddess actualize for a little while, and they had a bit of a chat.

After this, the bones were collected by Gaia Dynko and are now stashed in the Pole Land.