伝染病エンジン
アーティファクト
伝染病エンジンが戦場に出たとき、プレイヤー１人を対象とする。そのプレイヤーがコントロールする各クリーチャーの上に－１/－１カウンターを１個ずつ置く。
, 
：増殖を行い、その後再び増殖を行う。 （あなたはカウンターの置かれているパーマネントやプレイヤーを望む数だけ選び、その後それぞれに、その上にすでに置かれているカウンターのうち１種類を１個置く。 その後、それを繰り返す。）
イラスト：
Scars of Mirrodin#145レア日本語適正
裁定
You can choose any player that has a counter, including yourself.
You can choose any permanent that has a counter, including ones controlled by opponents. You can’t choose cards in any zone other than the battlefield, even if they have counters on them, such as suspended cards or a Lightning Storm on the stack.
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.
If a permanent chosen this way has multiple kinds of counters on it, only a single new counter is put on that permanent.
Players can respond to the 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.
As Contagion Engine’s activated ability resolves, you’ll complete an entire proliferate action, then you’ll complete a second proliferate action. You may choose different players and/or permanents, or different counters on those permanents, when you proliferate the second time.
Players can’t respond between the first and the second proliferate actions.