Bungie kind of snuck up on us with the challenge mode for Wrath of the Machine (it’s still running for King’s Fall by the way, if you care, like clockwork), a mystery task that you can complete on normal or hard for extra rewards. Well, it was a mystery for two hours after its launch until Reddit figured it out.
The gist is that you’ll need to take the bombs that fall after a Vosik damage phase, have two players take one bomb each, then split up and seal both blast doors with each bomb. Rinse and repeat on the second damage phase, then kill him on the third (you can use the bombs for damage at that point). Note that you need to kill him in three runs, as you are required to bomb four doors in total, otherwise you won’t clear the challenge. If you’re still struggling on normal you might not have the firepower to take him out in three runs, but most hard mode groups should have the arsenal required to pull it off (and may even need to hold back on the second damage phase).
In fact, this is the strategy my group employed anyway day one of the normal raid going in blind, as we erroneously thought we had to go in two seperate rooms (a glitch killed part of our group after we poured into the same sealed room, leading us to believe we had to split up), and we thought we had to use the bombs to seal the door before we figured out we could just shoot at the panel.
You’ll get an extra challenge chest containing a Siva armor ornament, boots, the challenge emblem, and a random special or heavy. Good luck! All signs point to a challenge for Aksis phase two next.