Edison format ruling
Van'Dalgyon the Dark Dragon Lord
Card text as printed in this era① If this card is in your hand, if the Activation of your opponent's Spell/Trap Card, or Monster Effect,
is negated by your Counter Trap (except during the Damage Step):
You can Special Summon this card.
② If you do, activate the appropriate effect(s) in sequence, depending on what was negated:
● Spell Card: Your opponent takes 1500 damage.
● Trap Card: Target 1 card your opponent controls;
destroy that target.
● Monster Effect: Target 1 monster in your GY;
Special Summon it.
Rulings
- You can only activate 1 Trigger Effect in your hand per chain. (You can't activate the ① effect of this card more that once per chain, even if you have multiple copies in your hand).
- The ① effect does not trigger when a Spell/Trap Effect is negated; it only triggers when the Spell/Trap itself is negated. (Activating a Spell/Trap Card from your hand is a Card Activation. Activating the effect of a Spell/Trap which is already face-up on the field is an Effect Activation).
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.