Bilbo's Stone Trolls

Bilbo's Stone Trolls enters the battlefield
tapped.
{t}: Add {1} to your mana pool.
{2}: Bilbo's Stone Trolls becomes a 2/2
Golem artifact creature until end of turn.
"They spent so much time arguing that the sun's
first light cracked over the top of the trees...and
turned them all to stone!" ~ Bilbo Baggins