エンチャント
いずれかのクリーチャーが場からいずれかの墓地に置かれるたび、それの上に-1/-1カウンターが置かれていた場合、クリーチャー1体を対象とし、それの上に-1/-1カウンターを1個置く。
When Blowfly Infestation’s ability resolves, it will put a single -1/-1 counter on the targeted creature. It doesn’t matter how many -1/-1 counters were on the creature that went to a graveyard as long as it had at least one on it.