Fungus Devourer

When Fungus Devourer enters the battlefield, decompose 4. (Exile up to four target cards from your graveyard. For each card exiled this way, create a 1/1 green Saproling creature token.)
{b}, {t}, Sacrifice a Saproling: Put a +1/+1 counter on Fungus Devourer, gain a life, then mill a card.
Something's got to keep them in check...