Ancient City - Rainbow Ruins

You must have this many "Crystal Beast" cards in your Spell & Trap Card Zone to activate and resolve these effects: // * 1+: This card cannot be destroyed by card effects. // * 2+: Once per turn, you can halve the Battle Damage you take. // * 3+: When a Spell/Trap Card is activated: You can send 1 "Crystal Beast" monster you control to the Graveyard; negate the activation and destroy it. // * 4+: Once per turn, during your Main Phase: You can draw 1 card. // * 5+: Once per turn, during your Main Phase: You can target 1 "Crystal Beast" card in your Spell & Trap Card Zone; Special Summon that target.