This challenge is part of Fortnite Season 4 Week 1 Challenges and you'll have to deal a total of 1,000 damage points to other players using Stark Industries Energy Rifles. The challenge isn't complicated in itself, once you know where to find the weapons in question. To collect some, all you need to do is go to one of the Quinjet Patrol Landing sites, which appear on your map with the following marker:
The floor-mounted devices are always guarded by a group of Stark robots. Shoot them down and you can retrieve precious Energy Rifles from these steaming heaps of bolts.
Note that Stark robots don't appear in the Team Rumble mode. To succeed in this challenge, you'll have to play Solo, Duo or Squad.
Epic Games had already integrated NPC spawns with specific weapons into the game in the past, such as the Stormtroopers during the Star Wars collaboration. Rest assured, these assault rifle variants are far from being overpowered.
Original content by Romain "Zorg" Becquelin.