Chronostutter

In Commander, Chronostutter occupies the low end of the acceptable-counterspell shelf — it answers a resolved creature at instant speed and denies the opponent a draw, which matters more in a singleton format where redundancy is scarce. The six-mana price tag is genuinely punishing in a format where Counterspell and Cyclonic Rift exist, so it mostly shows up in budget builds or decks that want redundant bounce effects. In Pauper, the common restriction makes it more competitive by comparison, and the tempo loss it inflicts on the opponent carries more weight in a lower-power environment. Legacy, Vintage, and Modern all have cheaper and more flexible interaction at every point on the curve, so Chronostutter sees essentially no play in those formats.