I solo'd the Valus T'aurc nightfall and thought "why don't I be a cool roommate and login to my buddy's Titan on his console and get him a free nightfall clear while he's at work?" So I do. I get the boss down to his last shot, go sit in the "cheese" spot under the ramp for safety while I log onto his Titan and join session. Once he's in there, I head back over to my room and kill him. He didn't have to shoot a single bullet, he didn't even have to touch his controller. I get a nice pack of 5 strange coins. Guess what my roommate gets? Gjallarhorn. The Gjallarhorn I'd been trying to get for 4-5 weeks at the time. All for doing literally nothing, without even being aware that he'd actually gotten it. He comes home and sees a Gjallarhorn in his inventory and asks me about it and I tell him what happened. He just laughs and says "thanks a lot" and goes on doing his daily routine. He doesn't even use it that much either. I've got two now so it's not as big of a deal anymore, but I was pretty furious at the time.