Wielder of the Pearl Trident

Submerg — {1}{u}{u} (You may cast this card for its Submerge cost. If you do, put it on the battlefield face down as a 1/1 creature with protection from red. Turn it face up any time it blocks or becomes blocked.)
When this card is turned face up, other Merfolk you control gain unblockable.
Other Merfolk you control get +1+1.