From Destinypedia, the Destiny wiki
A Chronology Rifle is a Vex weapon used exclusively by Dendron, Root Mind during A Garden World Strike. It works similarly to Vex Laser Rifles wielded by other Vex units and Trace rifles wielded by Guardians, but is much more powerful. The giant beam of energy can easily kill a Guardian in a few ticks if they're not hiding behind a wall. This weapon is the most dangerous when Dendron circles around the battlefield as it can sneak up behind Guardians if they are not aware of the situation.
List of appearances