Yalak's Skull was a scrying device created from the corpse of Yalak the Dragon Master by Azran Bedlam. Azran had long coveted Yalak's Egg, an extraordinarily powerful divination crystal. When he murdered the Dragon Master the Egg was not on his person, so Azran took his head instead and ensorcelled a scrying instrument from the skull.
Azran would ask the Skull questions about the future and it would respond, though often the answers were mystifying. It spoke on its own only once, around the same time that the Brown Dragon died in Cabe Bedlam's presence. What it said is not recorded, but in anger Azran shattered the skull.