Edison format ruling
Zombie World
Card text as printed in this era① All monsters on the field and in the GYs become Zombies.
② Neither player can Tribute Summon monsters face-up, except Zombies.
Rulings
- Players can still Tribute Set non-Zombies while this effect is applying.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.