Gengar, Mischief Shade

Fear, infect, haunt
When the creature Gengar haunts is destroyed,
you may put a ghastly from your Pokemon
sideboard onto the battlefield under your
control. Then you may return up to one target Haunter and up to one target Gengar you own
from exile or your graveyard to your Pokemon sideboard.
-Gengar cannot be in your starting deck.