This is a special type of gun used by Dark Eldar Haemonculi that fires a dart of very virulent poison into the victim's blood stream, causing them to explode! The stinger has the following profile:
Rng: 12" S: n/a AP: 6 Assault 1
The weapon does not have a Strength value as such, and always wounds a victim on a D6 roll of 2+. If the target is killed place a Blast marker centred on the exploding model and roll to hit other models using the rules for blast weapons. The attacks have a Strength equal to the exploding model's Toughness, and an AP value equal to the victim's saving throw (ie, models hit by an exploding Space Marine would take a S4 hit with AP 3). Stingers count as having a Strength of 1 if fired at a vehicle.