Pay 4 Force Untap one of your Starfighters in any arena. That Starfighter gets Area Damage 2 until end of turn. Play only when no unit is attacking.
Keywords
Area Damage
Area Damage X: A cumulative, triggered ability that means, "Whenever damage from this unit's attack causes a unit in this arena to be discarded, this unit may do X dice of damage to another unit in this arena."