Gengar

Pokeball 1 ( You can pay {1} and put this creature onto the battlefield face down, it is a 2/2
,you can turn it face up at any point by paying
it's mana cost )
When this card enters the battlefield, tap target creature, it doesn't untap during its owners next
untap step
When this card is turned face up, destroy target creature, or up to two tapped creatures