Tazri, Unified One

When Tazri, Unified One enters the battlefield,
you may search your library for a Phyrexian
creature card, reveal it, put it into your
hand, then shuffle.
{p/w}{p/u}{p/b}{p/r}{p/g}: Discard the top six cards
of your library. Creatures your opponents
control get -X/-X until end of turn, where X is
the number of colors used to pay for this ability.