Koa'ki Meiru Wall (SESL-EN050) [Secret Slayers]

During each of your End Phases, destroy this card unless you send 1 "Iron Core of Koa'ki Meiru" from your hand to the GY or reveal 1 Rock monster in your hand. When your opponent activates a Spell Card (Quick Effect): You can Tribute this card; negate the activation, and if you do, destroy that card.