Today's ghost pokémon is mismagius. I always thought it was kind of cute, I love the little hat. But then I read about it. It can put you to sleep, cause hallucinations, headaches and its cries sound like incantations or chanting. Creeeepy.
This pokémon needs no introduction. All I need to is quote it's Bulbapedia entry! It "hides in very dark places, where it plots to take the life of the next living thing that comes near it. It then silently stalks its victim and licks it in order to steal its life force, killing it by inducing continuous shuddering. It has the ability to float through solid walls."