Astral Arena | Magic: The Gathering
Formats Astral Arena is Legal in
Official Oracle Text for Astral Arena
No more than one creature can block each combat.
Whenever you roll , Astral Arena deals 2 damage to each creature.
Official Rulings for Astral Arena
6/1/2012 : If a turn has multiple combat phases, either a different creature or the same one can attack or block in each of them.