Siege of the Sixth Rainbow

When Siege of the Sixth Rainbow enters the battlefield and at the beginning of your upkeep,
choose one that hasn't been chosen
•Swing - At the end of combat on your turn,
untap all creatures you control, there is an additional combat phase after this one
•Get Swung - Tap all creatures you control, skip
your next combat phase, sacrifice Siege of the
Sixth Rainbow.