t: Add C.
1S: Until end of turn, Frostwalk Bastion becomes a 2/3 Construct artifact creature. It's still a land. (S can be paid with one mana from a snow permanent.)
Whenever Frostwalk Bastion deals combat damage to a creature, that that creature and it doesn't untap during its controller's next untap step.
illus. Jedd Chevrier # 240/254