Meandering Towershell

Meandering Towershell

Creature - Turtle | Power/Toughness: 5 / 9 (CMC 5)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Meandering Towershell attacks, exile it. Return it to the battlefield under your control tapped and attacking at the beginning of the declare attackers step on your next turn.