Scatter Arc

In Commander, Scatter Arc sits in the lower tier of counterspells — playable but not automatic, since four mana is slow and Counterspell, Arcane Denial, and Swan Song all do more for less. Outside of Melek, Reforged Researcher builds that want the cantrip stapled on, most blue decks will find better options first. In Pauper, where the card pool is tighter, Scatter Arc is a legitimate role-player: commons at this rate see real work in controlling shells. In Legacy, Modern, and Pioneer the competition is steep enough that it never sees play — those formats have access to free or one-mana counters that make four mana a non-starter.