mtg.wtf

Protection from red
Elemental creatures you control get +1/+1.
When Master of Waves enters, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue.

Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.

Enchant creature
When Claustrophobia enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Draw three cards.

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.

Counter target creature spell.

You may cast Harbinger of the Tides as though it had flash if you pay {2} more to cast it.
When Harbinger of the Tides enters, you may return target tapped creature an opponent controls to its owner's hand.

Islandwalk
When Inkfathom Divers enters, look at the top four cards of your library, then put them back in any order.

Other Merfolk creatures you control get +1/+1 and have islandwalk.

{T}: Draw a card, then discard a card.

Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.

Flying
When Merfolk Wayfinder enters, reveal the top three cards of your library. Put all Island cards revealed this way into your hand and the rest on the bottom of your library in any order.

Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.

Draw X cards.

You may exile a blue card from your hand rather than pay this spell's mana cost.
Change the target of target spell with a single target.

{T}: Rootwater Hunter deals 1 damage to any target.

Whenever Scroll Thief deals combat damage to a player, draw a card.

{T}: Target Merfolk creature gets +1/+1 and gains islandwalk until end of turn.
{T}: Target land becomes an Island until end of turn.

When Tidal Courier enters, reveal the top four cards of your library. Put all Merfolk cards revealed this way into your hand and the rest on the bottom of your library in any order.
{3}{U}: Tidal Courier gains flying until end of turn.

{T}: Target land becomes an Island until end of turn.

Create a 5/5 blue Wall creature token with defender. Sacrifice it at the beginning of the next end step.

When Tidebinder Mage enters, tap target red or green creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Tidebinder Mage.

Up to two target creatures each get +0/+3 until end of turn. Untap those creatures. At this turn's next end of combat, tap each creature that was blocked by one of those creatures this turn and it doesn't untap during its controller's next untap step.

Whenever a permanent you control becomes untapped, Wake Thrasher gets +1/+1 until end of turn.

Islandwalk
Whenever Cold-Eyed Selkie deals combat damage to a player, you may draw that many cards.