Advanced format ruling
Archfiend of Gilfer
Card effect (current official text)When this card is sent to the Graveyard: You can target 1 face-up monster on the field; equip that target with this card. That monster loses 500 ATK while equipped with this card.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.