Karn's Bastion
Land
, : Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
"I can't protect everyone here. But those I can, I will." —Karn
Legal in
Pioneer, Modern, Legacy, Vintage, Commander, Brawl, Historic
Rulings (6)
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.
2023-02-04
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.
2023-02-04
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.
2023-02-04
An ability that triggers "Whenever you proliferate" triggers even if you chose no permanents or players while doing so.
2023-02-04