Mage-Ring Responder [mana]7[/mana]
Artifact Creature - Golem
Rare
Mage-Ring Responder doesn't untap during your untap step.
7: Untap Mage-Ring Responder.
Whenever Mage-Ring Responder attacks, it deals 7 damage to target creature defending player controls.
7/7
Source: https://www.youtube.com/watch?v=TAFHjDKl2NQ