, : Untap target attacking creature you control. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

As long as Gaea's Liege isn't attacking, its power and toughness are each equal to the number of Forests you control. As long as Gaea's Liege is attacking, its power and toughness are each equal to the number of Forests defending player controls.

: Target land becomes a Forest until Gaea's Liege leaves the battlefield.

Flying

Vigilance (Attacking doesn't cause this creature to tap.)