Aquarnius, the Wave of Sea

Flying, islandwalk (This creature can't be blocked as long as defending player controls an Island.)
When Aquarnius, the Wave of Sea enters the battlefield, put a flood counter on each
non-Island land in play. Those lands are Islands
in addition to their other types for as long as they have a flood counter on them.
Aquarnius, the Wave of Sea toughness are equal
to the number of flood counters on lands in play.