Advanced format ruling
Fairy Box
Card effect (current official text)When your opponent's monster declares an attack: Toss a coin and call it. If you call it right, the attacking monster's ATK becomes 0 until the end of the Battle Phase. During each of your Standby Phases, pay 500 Life Points or destroy 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.