There's a mystery afoot during Destiny 2's Festival of the Lost event in the form of a secret Triumph that players have yet to figure out. While the Triumph is hidden in the game itself, players were able to see in the game's database that the Triumph is called Spider Vision with the objective to "See a spider in your sights." It is possible that the ability to complete the Triumph is time-gated to later on in the event, as Festival of the Lost is active until November 19th.
But that is not stopping players from theory-crafting and trying all sorts of methods to try to discover how they might be able to unlock this hidden Triumph. Some are theorizing that there is some sort of ADS screen gag similar to what happened in Spooky Trials in Destiny 1, where aiming down sights for too long in Trials would activate an animation of a spider crawling across the scope.
But with Trials not currently in Destiny 2, fans are not quite sure how this would be possible. The Trials game type, Elimination, is currently rotating through weekly iterations in the Crucible Labs playlist, so perhaps there will be a version similar to Spooky Trials (which also features no motion tracker or revives) that rotates in at some point during Festival of the Lost. A similar idea to this is that with another Iron Banner event starting next week during Festival of the Lost, perhaps the game will surprise players with a Spooky version of that special PvP event where the ADS gag might appear.
Other theories involve different variations of the idea of getting all five masks from Eva Levante and unlocking the Braytech Werewolf auto rifle that is exclusive to the event, and taking it into the Haunted Forest and aiming down sights with it. But at this point, no one has been able to get any theory along those lines to work.
Lastly, there is a theory that the Triumph ties into the Tangled Shore and the destination's vendor, the Spider. Despite the Spider having a part of the Toothbrush quest and the associate A Brilliant Smile Triumph, it does not appear that interacting with that character in any way has triggered anything related to the Triumph. It is very possible that players just simply have to wait until further into the Festival of the Lost before this Triumph is accessible, so, for now, we'll have to wait and see.
Destiny 2: Shadowkeep is available now for PC, PS4, and Xbox One, with a Stadia version also in development.