Planetback Tortoise

Vigilance, Hexproof
This creature costs {g}more to cast for each land you control.
This creature has +1/+1 for each land you control. Whenever Planetback Tortoise would attack, other creatures you control get +1/+1 for each land you control.
{t}: Add {g}{g} to your mana pool. Use this mana only to cast creature spells.