Darkrai

“It can lull people to sleep and make them dream. It is active during nights of the new moon.”

— Pokémon Diamond

“Folklore has it that on moonless nights, this Pokémon will make people see horrific nightmares.”

— Pokémon Pearl

“To protect itself, it afflicts those around it with nightmares. However, it means no harm.”

— Pokémon Platinum