History of Butterfly

Overview

Butterfly is a trait on several weapons, including Keraunios, Crux Celeritas IV, Eyes Unveiled and Vision of Confluence. Aim down sights for a short time without firing and the perk arms: the next final blow you land makes the target explode. The timer resets when you stop aiming down sights.

Its explosive value is in mob clearing. Sources do not give the exact aim time or the blast damage, so check the in-game description. Only third-party database pages were found for the text, not Bungie's own text.