Frostwalk Bastion — ruling 1

If you turn Frostwalk Bastion into a creature but haven't controlled it continuously since your most recent turn began, you won't be able to activate its mana ability or attack with it.

Frostwalk Bastion — ruling 2

A creature dealt combat damage by Frostwalk Bastion won't untap during its controller's next untap step, even if it was already tapped and even if Frostwalk Bastion leaves the battlefield before then.

Frostwalk Bastion : règles, fonctionnement et interactions (MTG)

Frostwalk Bastion is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

: 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.

How it works : Frostwalk Bastion

Original English text — Wizards of the Coast / Scryfall

#1June 14, 2019· Wizards of the Coast
If you turn Frostwalk Bastion into a creature but haven't controlled it continuously since your most recent turn began, you won't be able to activate its mana ability or attack with it.
No other card is named in this ruling.
#2June 14, 2019· Wizards of the Coast
A creature dealt combat damage by Frostwalk Bastion won't untap during its controller's next untap step, even if it was already tapped and even if Frostwalk Bastion leaves the battlefield before then.
No other card is named in this ruling.