The Flesh Forest

When you cast The Flesh Forest, you may pay
{3} or return it to its owner's hand. Each Mutant
creature you tap while paying for this ability pays
for {1} or one mana of that creature's color.
The Flesh forest enters the battlefield tapped.
{t}: Add {b} or {g}.
{1}, {t}: Add {b}{g} and 1 mana of any color. Use
this mana only to cast Mutant spells.