Frostwalk Bastion [Modern Horizons]

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 source.)
Whenever Frostwalk Bastion deals combat damage to a creature, tap that creature and it doesn't untap during its controller's next untap step.