Black Hole

Black Hole is a Commander card through and through — the scaling X cost and incidental life loss pay off most when games go long and boards get wide. In Legacy and Vintage it's legal but competes with a removal suite that operates at a far lower mana investment, so it rarely makes the cut outside of casual or experimental builds. Commander is where the card actually does its job: X sweepers that also dome opponents are exactly what slower, multiplayer games reward, and the venture synergy with The Most Dangerous Gamer pushes Black Hole into near-auto-include territory for that commander. Oathbreaker is the one other format worth mentioning, where high-impact sorceries can define a game, though the card sees little play there.