Expansion Algorithm

Format legality

Where you can play Expansion Algorithm in sanctioned and popular formats.

All printings (2)

Prices range from $2.45 to $2.51 across finishes. Cheapest printing: Secrets of Strixhaven Commander at $2.45.

More from Secrets of Strixhaven Commander

See all 426 cards in Secrets of Strixhaven Commander →

Rulings

Official rulings from Wizards of the Coast (6).

• 2026-03-20You don't have to choose every permanent or player that has a counter—only the ones you want to add counters 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.
• 2026-03-20If you proliferate multiple times, you don't have to choose the same set of players and/or permanents to get additional counters each time.
• 2026-03-20When you 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.
• 2026-03-20Players 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.
• 2026-03-20If 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.
• 2026-03-20While proliferating multiple times, players can't respond between proliferating the first time and proliferating the second time, and so on.

Frequently asked questions