Advanced format ruling
Half or Nothing
Card effect (current official text)During your opponent's Battle Phase (except during the Damage Step): Your opponent chooses 1 of these effects.
● Halve the ATK of all monsters they currently control, until the end of the Battle Phase.
● End the Battle Phase.
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.