The Hydra dwells in an alternate dimension and appears as a vast sea of gray ooze. A multitude of living heads, some human and some alien, sprout from the ooze, sobbing and grimacing as if in great agony. The Hydra's worshippers trick others into sending the god sacrifices through a pamphlet known as On the Sending Out of the Soul. The last page contains a magical formula for astral projection. When followed, the formula always works as expected, harmlessly transporting the user in astral form to whatever destination is desired. However, unbeknownst to the user, the ritual also brings the subject into contact with the Hydra, which then merges with the individual's astral self, using it as a host. Anyone present where the astral traveler appears is decapitated, the victim's head taken to become part of the Hydra. Afterwards, the astral traveler is returned safely to his or her original body, suffering no ill effects, except perhaps receiving a terrible shock from the grisly scene so witnessed.