Seiana, Tsunami's Origin

You may choose not to untap islands during
your untap step, if you don'tuntap it, put a
roil counter on it.
You may pay the mana cost of a Whale,
Leviathan, Octopus or Serpent by removing
roil counters equal to its converted mana cost
instead.

She rarely entertains the surface, like a child skipping stones across a lake, she finds contentment.