Aquatic Shaper

Whenever another monocolored blue card enters
the battlefield, create a water token (it's an
artifact with {1}, {t}: Create a copy of target
permanent you control with mana cost 3 or less.)
As long as you control 7 or more copies of the
same card, Aquatic Shaper becomes a 5/7 blue
elemental with flying until end of turn. When
this ability resolves, destroy all copies unless you
pay {x} where X is the number of copies you
would've sacrificed.