Kicker—Return a creature you control to its owner's hand. (You may return a creature you control to its owner's hand in addition to any other costs as you cast this spell.)
If Arctic Merfolk was kicked, it enters the battlefield with a +1/+1 counter on it.
: Return Darting Merfolk to its owner's hand.
Fading 4 (This creature enters the battlefield with four fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
Remove a fade counter from Jolting Merfolk: Tap target creature.
: Destroy target creature with islandwalk.
: Draw a card, then discard a card.
, : Target player puts the top two cards of his or her library into his or her graveyard.
When Merfolk Observer enters the battlefield, look at the top card of target player's library.
Flash (You may cast this spell any time you could cast an instant.)
Islandwalk
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)
: Tap target creature without flying.
When Merfolk Seer dies, you may pay . If you do, draw a card.
Flying
Whenever Merfolk Skyscout attacks or blocks, untap target permanent.
Other Merfolk creatures you control get +1/+1.
: Target Merfolk creature is unblockable this turn.
Islandwalk (This creature is unblockable as long as defending player controls an Island.)
Whenever Merfolk Spy deals combat damage to a player, that player reveals a card at random from his or her hand.
: Switch target creature's power and toughness until end of turn.
When Merfolk Traders enters the battlefield, draw a card, then discard a card.
When Merfolk Wayfinder enters the battlefield, 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.
: River Merfolk gains mountainwalk until end of turn.
Cycling (, Discard this card: Draw a card.)
As long as you control a Plains, Sejiri Merfolk has first strike and lifelink. (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)