Tengu format ruling
Big Shield Gardna
Card effect (current official text)When a Spell Card is activated that targets this face-down card (and no other cards) (Quick Effect): Change this card to face-up Defense Position, and if you do, negate the activation. If this card is attacked, change it to Attack Position at the end of the Damage Step.
Rulings
- A face-down Big Shield Gardna can only negate a Spell Card that targets 1 face-down monster, so it cannot negate Riryoku, Creature Swap or Dark Hole, but could negate Nobleman of Crossout or Tribute to the Doomed.
- If Big Shield Gardna is targeted with a Spell Card, you may chain Book of Moon to flip it face-down, then it can negate the Spell Card and will flip back to face-up Defense Position.
- Skill Drain only negates the effects of monsters that are face-up on the field, so a face-down Big Shield Gardna may still negate a Spell Card that targets it while Skill Drain is active on the field. It will still be flipped to face-up Defense Position, and now its effect that changes its battle position when it is attacked will be negated.
- If Prickle Fairy attacks a face-down Big Shield Gardna both their effects will occur at the end of the Damage Step. Prickle Fairy will be Step 1 and Big Shield Gardna Step 2. So it will change to Attack Position, and then the effect of Prickle Fairy will change it back to Defense Position.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.