Mystic Barrier, and Court of Vantress

Prerequisites

• Mystic Barrier on the battlefield
• Court of Vantress on the battlefield
• You have at least two opponents
• Court of Vantress on the battlefield as a copy of Mystic Barrier if you aren't the monarch

Steps

1. At the beginning of each of your upkeeps, Mystic Barrier and Court of Vantress triggers twice if you aren't the monarch, or once otherwise
2. Resolve the Mystic Barrier trigger, choosing "left"
3. If you aren't the monarch, resolve the Court of Vantress triggers, causing you to choose "right" and choosing to keep it as a copy of Mystic Barrier
4. Otherwise, resolve the Court of Vantress trigger, creating a token copy of Mystic Barrier, choosing "right" as the copy enters the battlefield
5. As long as there are three or more players in the game, creatures cannot attack

Results

• Creatures cannot attack