From Destinypedia, the Destiny wiki
Dark Drinker's special attack is Supermassive Vortex, a spin attack that damages all nearby enemies in any direction. This attack is useful for pushing back enemies in any direction, making it great for crowd control. It also comes equipped with Void Guard, which protects against Solar and Arc attacks, and increased armor. The weapon is especially useful for taking down high-level enemies since the special attack allow it to damage multiple hit-boxes in one use of its special attack.