Germoglio Cancrenoso

{1}, Sacrifica il Germoglio Cancrenoso: Scegli uno —
• Distruggi un artefatto bersaglio.
• Distruggi un incantesimo bersaglio.
• Prolifera.

Geschwürblüte

{1}, opfere die Geschwürblüte: Bestimme eines —
• Zerstöre ein Artefakt deiner Wahl.
• Zerstöre eine Verzauberung deiner Wahl.
• Führe Wucherung durch.

Gangrenoide

{1}, sacrificar el Gangrenoide: Elige uno:
• Destruye el artefacto objetivo.
• Destruye el encantamiento objetivo.
• Prolifera.

Chancreflore

{1}, sacrifiez le Chancreflore : Choisissez l'un —
• Détruisez un artefact ciblé.
• Détruisez un enchantement ciblé.
• Proliférez.

腐れ花

{1}, 腐れ花を生け贄に捧げる：以下から１つを選ぶ。
・アーティファクト１つを対象とする。それを破壊する。
・エンチャント１つを対象とする。それを破壊する。
・増殖を行う。

Flor-da-corrosão

{1}, sacrifique Flor-da-corrosão: Escolha um —
• Destrua o artefato alvo.
• Destrua o encantamento alvo.
• Prolifere.

散疡菌兽

{1}，牺牲散疡菌兽：选择一项～
•消灭目标神器。
•消灭目标结界。
•增殖。

Cankerbloom

{1}, Sacrifice Cankerbloom: Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Phyrexia: All Will Be One

{1}, Sacrifice Cankerbloom: Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Proliferate.

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.