Diabound Kernel (DUSA-EN026) [Duelist Saga]

When this card declares an attack: It gains 600 ATK. During either player's turn: You can target 1 face-up monster your opponent controls; it loses ATK equal to this card's current ATK until the end of this turn, then banish this card until the Standby Phase of the next turn. You can only use this effect of "Diabound Kernel" once per turn.