Simon Petrikov, the Ice King

Flying
{t}: Add {u} or {s}.
Whenever Simon Petrikov, the Ice King deals
combat damage to a creature, tap that creature.
It doesn't untap during its controller's next
untap step.
Madness {u}{u} (If you discard this card, discard it
into exile. When you do, cast it for its madness cost or
put it into your graveyard.)