Mordschlag (Dark Neostorm DANE-EN065) - Common Yu-Gi-Oh! Card

Equip only to a Normal Summoned/Set monster you control. It is unaffected by your opponent's activated effects of Special Summoned monsters. During damage calculation, if the equipped monster battles an opponent's Special Summoned monster: That opponent's monster loses ATK/DEF equal to the equipped monster's original ATK, during that damage calculation only.