Can I use Act of Aggression to steal their attacking creature and block with it?

Question

My opponent declares two creatures as attackers. I want to play Act of Aggression to gain control of one of their creatures and so I can have it block their other creature. Is this possible? Is so, during what step do I need to play my Act of Aggression? If I played it during my declare blockers step, would the creature that I now controlled still be attacking me?

Answer 1

Yes, that's fine. You would play the spell during the declare attackers step, after attackers are declared, but before proceeding to the declare blockers step. Then you are free to declare it as a blocker. If you wait for your declare blockers step, it's too late to block with the creature.

The ordering is:

• Declare Attackers Starts:
• Turn Based Action - Attackers are declared
• Players get Priority <- Cast Spell Now!
• Declare Blockers Starts:
• Turn Based Action - Blockers are declared
• Players get Priority <- Too late to use as blocker if cast now!

Any time a creature changes controllers, it is automatically removed from combat, so it will no longer be considered attacking you (or attacking/blocking at all if it previously was).