Airtaunos, The Elder Tree

Indestructible, Vigilance
Other Forests you control have indestructible.
Airtaunos can't attack or block unless you control
at least 7 other forests.
Whenever Airtaunos attacks, add 6{g}. This mana
isn't lost until the beginning of your next end step.
If this mana is used to cast a creature spell, it
enters the battlefield with an additional +1/+1
counter on it.