Advanced format ruling
Gigastone Omega
Card effect (current official text)This card cannot be Normal Summoned or Set. This card can only be Special Summoned by removing from play 2 EARTH monsters from your Graveyard. When this face-up card you control is sent to the Graveyard by a card effect, destroy all Spell and Trap Cards your opponent controls.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.