Rainbow Crystal Collection (SGX1-ENS14) - Speed Duel GX: Duel Academy Box 1st Edition

If a face-up "Crystal Beast" monster you control would be destroyed, you can place a Crystallization Counter on it instead. Monsters with Crystallization Counters are considered Continuous Spell Cards in your Spell & Trap Zone instead of monsters. If a card with a Crystallization Counter would be Special Summoned, remove the counter. Cards with Crystallization Counters can be used as Fusion Material for "Ultimate Crystal" monsters.