Lilly Gray: Victim of the Beast

The gravestone of Lilly Gray, victim of the beast, in the Salt Lake City Cemetery

In the Salt Lake City Cemetery there is a peculiar old gravestone that has been the source of much speculation. The small granite marker of Lilly Gray (1881-1954) bears the inscription Victim of the Beast 666.

Who was Lilly Gray and why would anyone put a statement like that on a gravestone?