Decade Stone
From Jenny Everywhere Wiki
The Decade Stone was a dangerous item on which the Crew of the Copper-Colored Cupids had a file. (PROSE: The Case Against Conspiracy)
Behind the scenes
A ‘Cupid Fact File’ on the Decade Stone was indeed published on the Crew of the Copper-Colored Cupids website a little under a year prior to The Case Against Conspiracy. However, it contained no Jenny Everywhere elements.