Moon Dregs is summoned through an unknown medium and takes the form of a large jellyfish with eyes on top of its head and numerous tendrils that hang from underneath its head.
To those that can't see curses, Moon Dregs make it appear as if Junpei is able to telepathically lift people and infect them with his poison. The poison takes the form of a deadly spotted rash that burns the victim similar to the scaring on Junpei's own forehead.
Moon Dreg's jellyfish body makes it capable of absorbing punches from even the likes of those with superhuman strength such as Yuji. Anyone caught in its tentacles will be paralyzed and infected with the toxin. Moon Dregs can also merge its tendrils together to form spikes that can inject the poison directly by stabbing Junpei's target. Even after the effects of the poison are removed, the targeted appendage will be burned and difficult to move.