Day of Black Sun (TLA)

Sorcery

Each creature with mana value X or less loses all abilities until end of turn. Destroy those creatures.

Niche board wipe for control and midrange decks, but the variable cost and ability-stripping clause make it awkward to cast efficiently—most matchups demand either unconditional removal or a cheaper sweeper like Damnation or Engineered Explosives.

Avatar: The Last Airbender — Rare