Gengar, The Gas PokÃ©mon. It is said to emerge from darkness to steal the lives of those who become lost in mountains. On the night of a full moon, if shadows move on their own and laugh, it must be Gengar's doing. Sometimes, on a dark night, your shadow thrown by a streetlight will suddenly and startlingly overtake you. It is actually a Gengar running past you, pretending to be your shadow. It is said that if it is hiding, it cools the area by nearly 10 degrees F. Lurking in the shadowy corners of rooms, it awaits chances to steal its prey's life force.