For the final legendary challenge in Week 12 of Fortnite Chapter 2 Season 7, you need to find three alien devices scattered throughout the map and use them to activate a countermeasure device in Corny Complex. The alien devices are floating purple orbs found exclusively in alien biomes. The good news is that you don’t need to complete all the stages of this challenge in the same game. However, not only are there just three alien devices in the entire map, you’ll also have to sneak past all of the IO guards in Corny Complex to activate the countermeasure device.
This week’s challenges ask us to craft a weapon using alien nanites, destroy target dummies with IO weapons, deploy scanners in alien biomes, and search for books on explosions. There’s a lot of stuff to find this week, so be sure to check our guides to find everything you need.
To help you finish this final challenge, we will go over all of the alien device locations you can find, as well as what you need to do to activate the countermeasure device.
Fortnite alien device locations
You need to find three alien devices before proceeding with the next step of the challenge. These are all of the alien device locations in Fortnite:
- Alien biome south of Corny Complex, past the bridge
- Between the curved rock and the alien trees southeast of the massive crater in the centre of the map
- Head east on the main road from Pleasant Park and cross the bridge. Turn right to head south towards Boney Burbs. To the left of the road close to the payphone, you’ll find the third alien device at the edge of the alien biome
How to activate the countermeasure device in Fortnite
To activate the countermeasure device, head to Corny Complex and enter the secret base via the underground entrance to the east of the red barn. From there, sneak around the ground floor clockwise until you find a room with a weird device in the centre of the room. Place all three alien devices into the countermeasure device to activate it.
By activating the countermeasure device, you should now have finished all of the legendary challenges for Fortnite Chapter 2 Season 7. Hopefully this will send those pesky trespassers packing. Before the end of the current season, you’ll want to ensure you’ve snapped up all of the Fortnite alien artifacts and Fortnite cosmic chests that you can in order to unlock as many Kymera styles. You can also check out our Fortnite Chapter 2 Season 8 release date guide for more info about what’s coming next season.