Salve of Bolas

When Salve of Bolas enters the battlefield, draw
a card, then discard a card unless you sacrifice a creature.
{u}{b}{r}, sacrifice Salve of Bolas: Target player sacrifices a creature, discards a card, and loses 2 life.
{u}{u}{b}{b}{r}{r}, exile Salve of Bolas: Target player sacrifices two creature, discards two cards, and loses 4 life.