The exotic weapon bounties require a lot of steps to complete. This one, I think, is for the Thorn Hand Canon. called A Light in the Dark. You need to do all of the following: Complete The Summoning Pits on the Moon. Earn 500 points by killing Hive enemies on the Moon. Use Void Damage to defeat Guardians in the Crucible. Death will slow your progress. Target is 500 points. 5 points gained per kill with Void damage weapons. 2 points lost per death. Obtain an Infusion of Light from The Speaker - this costs one Mote of Light. Talk to Ikora Rey. Kill Xyor, the Unwed. Xyor is found in a level 26 version of The Summoning Pits that is only available while this phase of the bounty is active. Phogoth must be damaged enough to trigger waves of enemies but not killed until Xyor appears. She is included in the enemies dropped by the third Tombship. Return to The Speaker to claim your reward. So still along way to go :(