This challenge is part of Fortnite Season 4 Week 4 Challenges and you'll have to destroy 20 gatherers. They're like little metal octopuses that attack you by firing red lasers. They're created by Gorgers — which appear randomly on Apollo Island.
The most difficult part of this challenge will be to find a Gorger. These large NPCs appear in very small quantities in each game. You'll have a hard time locating them, especially since they don't appear on the mini map.
There is only one way to increase your chances of finding the Gorgers: patrol over the island with a Helicopter! Choppas will allow you to survey the sky with a good visibility on what is happening below you.
Some helicopter locations
Forget about other vehicles and accessories: compared to the Choppa, they won't give you any overview to efficiently locate Galactus' robotic henchmen.
Note that the Gatherers' red shots can be seen from quite a distance. Try to focus on this color when you fly over the area.
Once you get out of your helicopter, all you have to do is break Gatherers. These small machines are quite fragile, but be careful: they explode once on the ground!
It's important to know that the levitating Gorger can produce an infinity of Gatherers. You can complete this challenge in a single attempt, by delaying the shots and letting the Gorger produce the 20 Gatherers needed for this challenge.
Original content by Romain "Zorg" Becquelin.