Serpent of the Shallows

{1}{u}: Adapt 1. Activate this ability only if
you control five or more Islands. (If this creature has no +1/+1 counters on it, put a
+1/+1 counter on it.)
Serpent of the Shallows can't attack unless it
has a +1/+1 counter on it.
Its appetite rises with the tide.