REDU format ruling
Giant Trap Hole

Nearest-era rulings (Tengu, Sept 2011) — no REDU-specific archive exists.
Card effect (current official text)When 2 or more monsters are Special Summoned at the same time: Destroy all monsters on the field.
Rulings
- You cannot activate "Giant Trap Hole" during the Damage Step.
- You can activate "Giant Trap Hole" when 1 monster is Special Summoned to each side of the field, by "The Shallow Grave", etc.
- You cannot activate "Giant Trap Hole" when "Grinder Golem" is Special Summoned.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the REDU forum — sourced change requests get reviewed.