Ath-Bhreith, The Waking Woods

Ath-Bhreith, The Waking Woods enters the battlefield tapped.
{t}: Add {w}, {b}, or {g}
{3}{w}{b}{g}: Until the end of turn, Ath-Bhreith,
The Waking Woods becomes an 6/8 white, black,
and green elemental legendary creature with
myriad. It is still a land.
—
The very forest rises against those who would intrude
on this sacred ground