Megatortle, Sky Fortress

Flying, Trample
Evolution Mastery: Whenever Megatortle attacks, if it has an Evolution counter on it, you may draw a card and gain 2 life.
Aqua Sonic Boom: {2}{g}{t}: Megatortle deals 3 damage to each tapped creature your opponent's control. If a creature would die this way, exile it instead.
Ultimate Shell Defense: {2}{u}: Prevent all combat damage that would be dealt to Megatortle this turn. If damage is prevented this way, put an Evolution counter on Megatortle.