Cast this spell only during your turn and only during combat before blockers are declared.
You choose which creatures block this combat and how those creatures block.
Whenever a creature attacks and isn’t blocked this combat, untap it and remove it from combat.
If a turn has multiple combat phases, this spell can be cast during any of them as long as it's before the beginning of that phase's Declare Blockers Step.
15-04-2013
wotc
An ability that triggers when something "attacks and isn't blocked" triggers in the declare blockers step after blockers are declared if (1) that creature is attacking and (2) no creatures are declared to block it. It will trigger even if that creature was put onto the battlefield attacking rather than having been declared as an attacker in the declare attackers step.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.