Locating a Firefly Burner in Arc Raiders is required for the final stage of the new Weather Monitor System project. Similar to the Comet Igniter, you'll have to defeat a Firefly, one of the two new arc enemies added in the update, in order to collect it. These enemies aren't too tough to kill, but you'll want to avoid them getting close and breathing fire on you.
The Shrouded Sky update also has some new tricky quests, such as A Rising Tide and Worth Your Salt, but by comparison, grabbing a Firefly Burner is a much easier task to accomplish.
How to get a Firefly Burner in Arc Raiders
You'll need to destroy one of the new Firefly arc enemies to get a Firefly Burner. Unlike the Comet Igniter, this item is far easier to get, since it seems to drop with almost every Firefly kill, similar to a Hornet or Wasp Driver.
The Firefly is a flying arc similar to a Hornet, except that it gets in close and sets you aflame like a Fireball. You can find them on every map, but I've had the most luck on Dam Battlegrounds around the Hydroponic Dome Complex and in the swamp. This area has always been incredible for flying arcs—just be somewhat cautious you don't accidentally aggro a Rocketeer if one happens to be nearby. Fireflies look a little like Hornets, except that they have a slightly more pointy shape, like a jet fighter, and they look like they're wearing a little hat because of the extra metal plate on top of them. If you're unsure, remember you can tag enemies to find out what they are.
Despite their different visual appearance, you kill a Firefly the same way as a Hornet—you want to either shoot its back two rotor fans or blast away the armour on its front two fans to take those out. As ever, a Ferro will serve, but an Anvil would be better. If you want a cheap and dirty solution, I recommend Seeker Grenades, since, as I learned in the Shared Watch event, they absolutely decimate flying arc enemies.
The key difference is that the Firefly will just melt you if it gets in close and, unlike with a Hornet, you won't have much chance of dodging the fire it spews, so you'll want to take it out as fast as possible, or hide in a building to plink at it. Once destroyed, loot its corpse and you'll find a Firefly Burner.
