This is aimed at year 1 guardians, where the Gjallarhorn was either RNG or folks smart enough to have enough strange coins from running a couple heroic strikes (18 coins) and spend 17 on a heavy exotic (who would ever do that???)
Simple enough, I spent Vanilla and Dark Below without a Gjallarhorn, no one in my clan had one. When House of Wolves dropped I was on a business trip. I flew home late and hopped onto Destiny because like many I am addicted. I was too tired to shoot, so I hit old Rahool the tool with my single blue chest engram. Reward? Blue chest engram of course, but it leveled me up in the Cryptarch, this gave me a legendary engram, which I leisurely popped and BOOM. That sweet sweet sound of an exotic drop. It was the Gjallarhorn I had chased for so long. Heck, I even had two crux's drop already before this.
I was stunned and in shock. I took a pic of the screen immediately and woke up my fourteen-year-old son, at 4:00am! "You've gotta come here."
I kept him up while I took it out to shoot. It was amazing! It took a bit to level up as veterans will no doubt recall, motes were not a way to level up guns and those wolf pack rounds were not an intrinsic perk like they are now. It was the last damn node, just behind the additional damage nodes. Ahh memories.
My second dropped a week later as a nightfall reward haha. I have kept both since then in my vault. One leveled and used for so much and one completely untouched. But those memories.