"Your only existence shall be that which I weave for you out of sorrow and woe."
To unlock this sniper rifle (basically a Y2 310 Exotic Black Hammer (post-nerf, so it still sucks and wastes an Exotic slot, and doesn't even have a new perk)), you must try to board Wolfship Kaliks-Syn (Taniks' Ketch) in Lost to Light on Heroic. You will have ten minutes to kill every single Taken in the area, and a Taken Ultra Captain. If you succeed, the Black Spindle is yours.