Verseuchter Beobachter

Fliegend
Toxisch 1 (Spieler, denen von dieser Kreatur Kampfschaden zugefügt wird, erhalten außerdem eine Giftmarke.)
Immer wenn eine andere Kreatur unter deiner Kontrolle ins Spiel kommt, kannst du {2} bezahlen. Falls du dies tust, 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.)

Observador contaminado

Vuela.
Tóxico 1. (Los jugadores que reciben daño de combate de esta criatura también obtienen un contador de veneno.)
Siempre que otra criatura entre al campo de batalla bajo tu control, puedes pagar {2}. Si lo haces, prolifera. (Elige cualquier cantidad de permanentes y/o jugadores, luego pon sobre cada uno un contador de cada tipo que ya tenga.)

Observateur souillé

Vol
Toxique 1 (Les joueurs qui subissent des blessures de combat de cette créature gagnent aussi un marqueur « poison ».)
À chaque fois qu'une autre créature arrive sur le champ de bataille sous votre contrôle, vous pouvez payer {2}. Si vous faites ainsi, 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.)

Osservatore Contaminato

Volare
Tossico 1 (I giocatori a cui viene inflitto danno da combattimento da questa creatura ottengono anche un segnalino veleno.)
Ogniqualvolta un'altra creatura entra nel campo di battaglia sotto il tuo controllo, puoi pagare {2}. Se lo fai, prolifera. (Scegli un qualsiasi numero di permanenti e/o giocatori, poi metti su ognuno un altro segnalino di ogni tipo già presente.)

汚れた観察者

飛行
毒性１（このクリーチャーから戦闘ダメージを受けたプレイヤーは追加で毒カウンター１個を得る。）
これでないクリーチャー１体があなたのコントロール下で戦場に出るたび、あなたは{2}を支払ってもよい。そうしたなら、増殖を行う。（望む数のパーマネントやプレイヤーを選び、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。）

Observador Maculado

Voar
Tóxico 1 (Os jogadores que sofrem dano de combate desta criatura também recebem um marcador de veneno.)
Toda vez que outra criatura entra no campo de batalha sob seu controle, você pode pagar {2}. Se fizer isso, 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.)

败坏侦鸟

飞行
下毒1（受此生物战斗伤害的牌手还会得到一个中毒指示物。）
每当另一个生物在你的操控下进战场时，你可以支付{2}。若你如此作，则增殖。（选择任意数量的永久物和／或牌手，然后为其已有之每种指示物各多放置一个同类的指示物。）

Tainted Observer

Flying
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever another creature you control enters, you may pay {2}. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Phyrexia: All Will Be One

Flying
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever another creature enters the battlefield under your control, you may pay {2}. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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

A player with ten or more poison counters loses the game. This is a state-based action and doesn't use the stack. In other words, it happens immediately and players can't respond to it, just like a player losing the game due to having 0 or less life.

Any other effects of that damage, such as life gain from lifelink, still apply.

Conversely, replacement effects that apply to the number of counters put on a player can modify the counters placed this way. For example, Vorinclex, Monstrous Raider's last two abilities can apply to counters placed this way.

Damage dealt by a creature with toxic grants the same number of counters regardless of how much damage is dealt. Notably, if a replacement effect modifies the damage in some way (such as that of Gratuitous Violence), the number of counters given remains unchanged.

If a creature with toxic deals combat damage to a creature or planeswalker, or if it deals noncombat damage, toxic has no effect and no player gets poison counters.

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.

Multiple instances of toxic are cumulative. For example, if a creature has toxic 2 and gains toxic 1 due to another effect, combat damage that creature deals to a player will cause that player to get 3 poison counters.

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.

Toxic doesn't change the amount of combat damage a creature deals. For example, if a 2/2 creature with toxic 1 deals combat damage to a player, that creature will deal 2 damage. The results of that damage are the player loses 2 life and gets a poison counter.

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.