Wyvern Shore

({t}: Add {u} to your mana pool.)
At the beginning of your end step, if you control three other Islands and Wyvern Shore
isn't a creature, you may put three +1/+1 counters on it. If you do it becomes a 0/0 blue Dragon creature with defender and flying. It's still a land.
Puddles, reasonably safe. Ponds, probably fine. Lakes, begin to worry me. Don't go near an ocean!