Enchantment, 3R (4)
Uncommon
Whenever an opponent casts a creature spell, Æther Sting deals 1 damage to that player.
When Gatha fell, he was called to account for each abomination he created.
Illus. Pete Venters

10/1/2009: The ability triggers when an opponent casts a creature spell, and goes on the stack above that spell. As such, the ability will deal 1 damage to that player before the creature enters the battlefield.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander