Removing attacking creatures via untapping them

[healo]

Hi,

we have an argument with my friend. He says I can not prevent damage from attacking creature by untapping it. I believe it is possible to react to declaring attackers, for example by untapping it. The reason I strongly believe this is the case is that I clearly remember I have untapped Blightsteel Colossus many times with Voltaic Key, making it deal no damage to me. But does it work tha same way with other creatures? For Example Master Decoy and random 2/2 attacking creature?

Thank you, hopefully I am right, or else I will have to drink like 10 shots in a row

[H]

Sorry, but your understanding is incorrect.  From the comprehensive rules:

506.4b Tapping or untapping a creature that’s already been declared as an attacker or blocker doesn't remove it from combat and doesn't prevent its combat damage.

What you might have been thinking is that Tapping an attacker can prevent it from being declared an attacker, if done in the Beginning of Combat Step, but Untapping has no real effect except to make the creature an untapped attacker.

[Meddling Mike]

I was wondering if perhaps some of this confusion might come from having seen Maze of Ith used? H is absolutely correct, untapping a creature alone does not remove it from combat. It only works in the case of Maze of Ith specifically because the card states that using the ability removes the creature from combat. Your example with the Blightsteel Colossus and Voltaic Key also does not work. Blightsteel would still be attacking despite being untapped in that scenario.



Master Decoy is another matter entirely. Master Decoy taps creatures, it does not untap them. If you were to tap a creature before it can be declared as an attacker it is not able to attack if it is already tapped at the time you declare attackers.

[Clariax]

 It only works in the case of Maze of Ith specifically because the card states that using the ability removes the creature from combat.

Maze of Ith does not state anything about removing a creature from combat.  Maze of Ith prevents damage.  The creature in question is still very much attacking, can be blocked, etc.