Instant, 1R (2)
Common
Guerrilla Tactics deals 2 damage to target creature or player.
When a spell or ability an opponent controls causes you to discard Guerrilla Tactics, Guerrilla Tactics deals 4 damage to target creature or player.
Illus. Randy Asplund-Faith

10/4/2004: If it is discarded, the damage done by it is done by this card due to an ability and not by a spell.
10/4/2004: The second ability will trigger even on an optional discard caused by an opponent.
10/4/2004: Discarding as a cost to cast a spell will not trigger the ability. Only discarding as an effect will trigger the ability.
Legal in Vintage (Type 1)
Legal in Legacy (Type 1.5)
Legal in Classic (MTGO)
Legal in Commander
Legal in Modern