Edison format ruling
Light and Darkness Dragon
Card text as printed in this eraⓈ Cannot be Special Summoned.
① This face-up card on the field is also a DARK.
② Once per Chain, if a Spell/Trap Card, or Monster Effect, is activated (Quick effect):
This card loses exactly 500 ATK/DEF and that activation is negated.
③ If this card is destroyed and sent to the GY:
Target 1 monster in your GY (if possible);
destroy all cards you control (regardless),
also, after that, Special Summon that monster (if any).
Rulings
- For the mandatory ② effect to resolve, this card must be able to both negate the activation and also lose exactly 500 ATK and 500 DEF. If you can’t do either, you do neither.
- Vs Spirit Monsters, Lyla, Treeborn Frog, Vayu, etc: These trigger effects will be negated by this card’s ② effect, and can then trigger again. (This can "loop" until Light and Darkness Dragon can’t lose any more ATK/DEF.)
- The ③ effect can cause effects, to have incorrect activation timing.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.