Tengu format ruling
Ground Spider
Card effect (current official text)Once per turn, if you control this face-up Defense Position monster when your opponent Normal or Special Summons a monster(s), you can change that monster(s) to Defense Position.
Rulings
- This effect does not target.
- If Ground Spider is no longer on the field when its effect resolves, the monster will still be switched to Defense Position.
- If your opponent Special Summons multiple monsters and at least one of them is Summoned in Attack Position, you can activate this effect.
- If your opponent Special Summons multiple monsters and you activate this effect, all of the Summoned monsters are changed to Defense Position.
- You cannot activate this effect during the Damage Step.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.