Vortex

Vortex is a Voidwalker Warlock super augmentation that changes Nova Bomb into a singularity. After detonation the blast radiates for 7 seconds, damaging enemies inside, and final blows with it activate Devour.

Details

Destiny 2 Wiki lists 24 damage per tick, and a patch 2.8.0 change (duration 5 to 7 seconds, damage 27 to 24, projectile speed +33%, Devour on kills). Those numbers may have changed since. The alternative is Cataclysm.