Ancient City - Rainbow Ruins * Common * SDCB-EN018You must have this many "Crystal Beast" cards in your Spell & Trap Card Zone to activate and to resolve these effects. 1+: This card cannot be destroyed by card effects. 2+: Once per turn (including the opponent's) you can halve the Battle Damage you take. 3+: During either player's turn, when a Spell Trap Card is activated: You can send 1 "Crystal Beast" monster you control to the Graveyard; negate the activation, and if you do, destroy it. 4+: Once