Erby, the Mighty Protector

Erby, the Mighty Protector enters the battlefield tapped.
{t}: Add {g}{g} to your mana pool.
As long as Erby, the Mighty Protector is untapped, it gets +2/+2 and has trample.
Erby, the Mighty Protector can block an additional creature each combat.
"From deep within the heart of the forest, Erby rises, a towering force of nature. With every step, the earth quakes and his enemies tremble."