Mystic Barrier | Clever Impersonator

Cards

Mystic Barrier and
Clever Impersonator on the battlefield (
Clever Impersonator as a copy of
Mystic Barrier).
You have at least two opponents.

At the beginning of each of your upkeeps,
Mystic Barrier and
Clever Impersonator trigger, choosing "left" for
Mystic Barrier and "right" for
Clever Impersonator.
As long as there are three or more players in the game, creatures cannot attack.