Under a full moon, this POKéMON likes to mimic the shadows of people and laugh at their fright.
A GENGAR is close by if you feel a sudden chill. It may be trying to lay a curse on you.
It steals heat from its surround ings. If you feel a sudden chill, it is certain that a GENGAR appeared.
To steal the life of its target, it slips into the prey's shadow and silently waits for an opportunity.
Hiding in people's shadows at night, it absorbs their heat. The chill it causes makes the victims shake.
— Pokédex entries (via PokeAPI)