MANGROVIA COUNTERSPELL

Creatures you control have "{T}: Add one mana of any color."

Whenever one or more nontoken Merfolk you control become tapped, create a 1/1 blue Merfolk creature token with hexproof.

Whenever Fallowsage becomes tapped, you may draw a card.

Creatures don't untap during their controllers' untap steps.

Whenever a creature enters the battlefield, untap all creatures.

({T}: Add {U}.)

Whenever a Merfolk you control becomes tapped, you may gain 1 life.

Tap another untapped Merfolk you control: Kumena, Tyrant of Orazca can't be blocked this turn.

Tap three untapped Merfolk you control: Draw a card.

Tap five untapped Merfolk you control: Put a +1/+1 counter on each Merfolk you control.

Whenever a spell or ability you control counters a spell, you may create a 1/1 blue Merfolk creature token.

Tap seven untapped Merfolk you control: Counter target spell.

Other Merfolk creatures you control get +1/+1.

Whenever you cast a Merfolk spell, you may tap or untap target permanent.

As an additional cost to cast this spell, tap four untapped creatures you control.

Draw three cards.

Whenever Stonybrook Schoolmaster becomes tapped, you may create a 1/1 blue Merfolk Wizard creature token.

At the beginning of each end step, if an opponent lost 3 or more life this turn, you may draw a card. (Damage causes loss of life.)

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

{1}{W}: Target Merfolk you control gains protection from the color of your choice until end of turn.

If it's neither day nor night, it becomes day as The Celestus enters the battlefield.

{T}: Add one mana of any color.

{3}, {T}: If it's night, it becomes day. Otherwise, it becomes night. Activate only as a sorcery.

Whenever day becomes night or night becomes day, you gain 1 life. You may draw a card. If you do, discard a card.

Flash

Other Merfolk you control get +1/+1.

Sacrifice a Merfolk: Counter target noncreature spell unless its controller pays {1}.