flavorText: "You didn't say the Magic word."
name: Common Courtesy
originalText: Counter any spell unless its caster asks your permission to play that spell. If you refuse permission, Sacrifice Common Courtesy and counter the spell.
printings: UGL, UND
text: Whenever a player casts a spell without asking your permission while casting it, counter that spell.
  When a player asks you permission to cast a spell and you refuse, counter that spell and sacrifice this enchantment.
type: Enchantment