Activate this card by targeting 1 Synchro Monster you control. That target cannot be destroyed by battle or by your opponent's card effects. At the start of the Damage Step, if that target battles an opponent's Level 5 or higher monster: You can destroy the opponent's monster, and if you do, that target gains ATK equal to the original ATK of the monster destroyed by this effect until the end of this turn. If that target leaves the field, destroy this card.
Atom 1.0
