Flatten

In Commander, Flatten competes in the most removal-dense format in the game, and four mana at sorcery speed is a steep ask when the table has three opponents threatening creatures, artifacts, and enchantments simultaneously. Pauper is the one format where Flatten sees any real consideration, since the commons card pool trims the competition enough that four-mana catch-all removal becomes more palatable. In Legacy, Modern, and Pioneer the card is legal but effectively invisible — formats that punish tempo losses this severe have no use for it. Oathbreaker and Vintage follow the same logic as Commander: better options exist at every price point.