Vel'Koz, Eye of the Void

Ward- Pay 3 life.
{1}{u}{b}, {t}: Discard up to three cards, for each
card dicarded this way put a -1/-1 counter on up
to three creatures, not named Vel'Koz, Eye of
the Void.
When a creature with a -1/-1 counter on it and
0 toughness dies, draw a card. This effect triggers
only once each turn.