Koa'ki Meiru Sea Panther

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 WATER monster in your hand. Once per turn, you can send 1 "Iron Core of Koa'ki Meiru" from your hand to the GY to return 1 Spell Card from your GY to the top of your Deck.