Trample

As long as you control no creature land, Slumbering Troll is a Mountain Forest land.

Awaken 4—{6}{R}{G} (If you cast this spell for {5}{R}{G}, also put four +1/+1 counters on target land you control and it becomes a 0/0 Elemental creature with haste. It’s still a land.)

As Slumbering Troll awakens a land, it beomes a Troll in addition to its types and gains trample.