J. Ari Hilliard was a man who was part of the Atlantis Endeavor, a time-traveling mission whose base was located on the moon. He discovered a way to make himself immortal, but eventually decided that he wanted to die. After his followers turned against him, he fled to Earth, hundreds of years in the past, where he tried and failed to kill himself. He then waited for himself to be born on the moon, so he could kill his own infant self, thus preventing his own existence. ("Lunopolis")