Frostwalk Bastion
From Modern Horizons set
Frostwalk Bastion
Snow Land
: Add .
: Until end of turn, this land becomes a 2/3 Construct artifact creature. It's still a land. ( can be paid with one mana from a snow source.)
Whenever this land deals combat damage to a creature, tap that creature and it doesn't untap during its controller's next untap step.