A couple of years ago, I participated in Oddvent. This was my contribution:
The Book of Crushing Force
Swindled ages ago from its deeply filed place in the Great Library of Bastion, The Book of Crushing Force has since found itself in countless libraries across the failed cities of the Deep Country. It is said to contain truths so heavy that it could crush the head of the unworthy.
The book, powerful as it is, requires a WIL save to open. A failure will cause the book to assume such tremendous weight that it will drop to the floor, through the floor, and all floors beneath, to the ground, through that ground, and all grounds beneath, to the physical bottom of space and below that.
On a success, the book will provide the character with a single piece of undeniably remarkable campaign knowledge that they may use to destroy the entire fabric of the game world. Once.