Card Guard (EGS1-EN011) - Egyptian God Deck: Slifer the Sky Dragon 1st Edition

If this card is Normal or Special Summoned: Place 1 Guard Counter on it. This card gains 300 ATK for each Guard Counter on it. Once per turn: You can target 1 other face-up card you control; remove 1 Guard Counter from this card, and if you do, place 1 Guard Counter on that target (if that card would ever be destroyed, remove 1 Guard Counter from it instead).