Dimension Sphinx (MVP1-EN023) - The Dark Side of Dimensions Movie Pack 1st Edition

Activate this card by targeting 1 face-up Attack Position monster you control. Once per battle, during the Battle Step, if it is attacked by an opponent's monster with higher ATK: You can inflict damage to your opponent equal to the difference between the attacking monster's ATK and the targeted monster's. If the targeted monster leaves the field, destroy this card.