Akrellung, Scourge of Geth

When Akrellung, Scourge of Geth enters the battlefield Plunder {x} where {x} is equal to the
number of Fish, Mutants and Pirates on the battlefield. (Exile {x} target cards from opponents graveyards, then create {x} colorless treasure artifacts
that have "{t} sacrifice: to add one mana of any color
to your mana pool" for each card exiled this way.
Other Fish, Mutants and Pirates get +1/+0 when attacking