Some time ago, there was a mob spawn exploit/glitch on Urstar fish Sabotage missions that would teleport dozens of freshly spawned mobs onto one point. You could sit on a perch with a Hushed Tonkor and lob grenades at the point, netting you a ludicrous amount of affinity, credits, resources, and the occasional rare mod. It took literally minutes to rank your gear up to 30 (20 mid-mission, which got a bonus post mission, raising it to 30, from 0) with the help of a friend. It would also level your Archwing gear, due to its location.
Right now, that exploit is only half fixed. Mobs will still teleport to that point, but will be a corpse. They still drop their loot in their original spawn locations, however, which is great for farming mods, resources, and credits.