Is Frostwalk Bastion legal in Standard, Modern, and Commander?

Frostwalk Bastion is legal in: Modern, Legacy, Vintage, Commander.

What type of card is Frostwalk Bastion?

Frostwalk Bastion is a Snow Land. Its oracle text reads: "{T}: Add {C}. {1}{S}: Until end of turn, this land becomes a 2/3 Construct artifact creature. It's still a land. ({S} 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."