Bringers of Dark Omen

Flying, protection from the chosen creature
When Bringers of Dark Omen enters the battlefield, choose a creature. When the chosen creature dies, you may sacrifice Bringers of Dark Omen. If you do, draw a card.
{1}{b}, {t}: The chosen creature gets -X/-X until end of turn, where X is the number of creature cards in target player's graveyard. If it dies this turn, draw a card.