Scrapyard Warforged

When Scrapyard Warforged enters the
battlefield, each player mills 6 cards.
Scrapyard Warforged's power and toughness are
equal to the number of artifacts in all graveyards.
At the begginning of your upkeep, you lose 1 life.
{1}{b}, Sacrifice an artifact: Each creature gets
-1/-1 until end of turn.