Meervolk-Himmelstaucherin

Fliegend
Wenn die Meervolk-Himmelstaucherin ins Spiel kommt, lege eine +1/+1-Marke auf eine Kreatur deiner Wahl, die du kontrollierst.
{3}{G}{U}: Führe Wucherung durch. (Bestimme eine beliebige Anzahl an bleibenden Karten und/oder Spielern und gib ihnen dann von jeder Sorte Marke, die dort bereits liegt, eine weitere Marke.)

Planeadora tritón

Vuela.
Cuando la Planeadora tritón entre al campo de batalla, pon un contador +1/+1 sobre la criatura objetivo que controlas.
{3}{G}{U}: Prolifera. (Elige cualquier cantidad de permanentes y/o jugadores, luego pon sobre cada uno un contador de cada tipo que ya tenga.)

Plongeuse céleste ondine

Vol
Quand la Plongeuse céleste ondine arrive sur le champ de bataille, mettez un marqueur +1/+1 sur une créature ciblée que vous contrôlez.
{3}{G}{U} : Proliférez. (Choisissez n'importe quel nombre de permanents et/ou de joueurs, puis donnez-leur à chacun un autre marqueur de chaque sorte déjà présente.)

Tritona Veleggiante

Volare
Quando la Tritona Veleggiante entra nel campo di battaglia, metti un segnalino +1/+1 su una creatura bersaglio che controlli.
{3}{G}{U}: Prolifera. (Scegli un qualsiasi numero di permanenti e/o giocatori, poi metti su ognuno un altro segnalino di ogni tipo già presente.)

マーフォークのスカイダイバー

飛行
マーフォークのスカイダイバーが戦場に出たとき、あなたがコントロールしているクリーチャー１体を対象とする。それの上に＋１/＋１カウンター１個を置く。
{3}{G}{U}：増殖を行う。（望む数のパーマネントやプレイヤーを選び、その後すでにそこにあるカウンター１種類につき、そのカウンターをもう１個与える。）

Mergulhadora Celeste Tritã

Voar
Quando Mergulhadora Celeste Tritã entrar no campo de batalha, coloque um marcador +1/+1 na criatura alvo que você controla.
{3}{G}{U}: Prolifere. (Escolha qualquer número de permanentes e/ou jogadores. Em seguida, dê a cada um deles outro marcador de cada tipo que eles já tenham.)

Merfolk Skydiver

Flying
When this creature enters, put a +1/+1 counter on target creature you control.
{3}{G}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

The Lost Caverns of Ixalan Commander

Flying
When Merfolk Skydiver enters the battlefield, put a +1/+1 counter on target creature you control.
{3}{G}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

War of the Spark

You may choose Merfolk Skydiver as the target of its own ability.

An ability that triggers "Whenever you proliferate" triggers even if you chose no permanents or players while doing so.

If a permanent ever has both +1/+1 counters and -1/-1 counters on it at the same time, they're removed in pairs as a state-based action so that the permanent has only one of those kinds of counters on it.

If a player or permanent has more than one kind of counter on it, and you choose for it to get additional counters, it must get one of each kind of counter it already has. You can't have it get just one kind of counter it already has and not the others.

Players can respond to a spell or ability whose effect includes proliferating. Once that spell or ability starts to resolve, however, and its controller chooses which permanents and players will get new counters, it's too late for anyone to respond.

To proliferate, you can choose any permanent that has a counter, including ones controlled by opponents. You can choose any player who has a counter, including opponents. You can't choose cards in any zone other than the battlefield, even if they have counters on them.

You don't have to choose every permanent or player that has a counter, only the ones you want to add another counter to. Since "any number" includes zero, you don't have to choose any permanents at all, and you don't have to choose any players at all.