Excommunicate

In Commander, Excommunicate is too slow and too impermanent to earn a slot — three mana at sorcery speed to set an opponent back one turn is rarely enough when you're facing three other boards. Pauper is where Excommunicate sees its most legitimate play, since the common card pool is constrained enough that topdeck manipulation matters and tempo swings hit harder. In Legacy and Vintage the card is legal but irrelevant; those formats answer threats with hard removal or counterspells at a fraction of the cost. Oathbreaker can occasionally leverage the delayed-draw punishment in aggressive white shells, but even there better options exist.