Deathrite Lifefarmer

Undergrowth - Deathrite Lifefarmer enters the
battlefield with a +1/+1 counter on it for each
creature card in your graveyard.
Dredge 4, Scavenge {1}{b}{g}.
{t} Exile target card from your graveyard.
When any card leaves your graveyard; if it is a
Creature you gain 2 life, if it is an Instant or
Sorcery: Each opponent loses 2 life; and if it is a
Land, one mana of any color, {b}{b} or {g}{g}.