So my team just beat Crota a little over an hour ago on Hard, and all I was wanting was the Fang of Ir Yut, because I use Scout Rifles more than any other primary. Much to my delight, it was my one weapon drop from Crota (along with some shards and Glowhoo). I immediately went and did every leftover bounty for today and unlocked the Target Mark ability. I figured I'd just make a quick video about how it functions in game. As you can see, it simply puts a green beam of light above the enemy affected, and can only be applied to one enemy at a time. A few things I forgot to show: 1. The mark only lasts 5 seconds. I realized I killed a lot of stuff too quickly to show that. 2. Unlike the Hive Disruptor perk on all the raid weapons, Target Mark is not added on, but rather replaces Spray and Play, meaning you can only have one or the other active. 3. (Edited in) You cannot see the mark through walls, you can only see the beam over low lying cover like the box in the video. Edit: Clarifying that teammates can see the mark. I assumed it would, but didn't want to say it does without testing.