Edison 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.
Rulings
- "Half or Nothing" cannot be activated during the Damage Step. The effect of "Half or Nothing" that halves ATK only applies to monsters face-up on the field at that time. Monsters flipped face-up, or Summoned, afterwards are not affected.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.