Crystalline Eye of Undravius
Quest reward from Ancient War Remnants. UPDATE: Rare solves in Legion will be obtained in a different way than previous expansions - see below!
The 
Crystalline Eye of Undravius is a Legion Archaeology rare solve toy that, when used, transforms all nearby players and NPCs into Demons and fills the sky with falling demons and green air effects.
Guide awaiting review
Level Legion Archaeology
Train and practice Archaeology in Legion zones to unearth artifacts. The Crystalline Eye of Undravius is a rare solve from the Legion Archaeology artifact pool, meaning it will appear as a solvable project as you dig up fragments across Legion zones.
Solve Rare Legion Artifacts
Unlike rare solves in previous expansions, rare solves in Legion are obtained through a different method — continue solving Legion Archaeology projects until the Crystalline Eye of Undravius appears as an available rare project for you to complete.
Use the Toy
Once obtained, activate the Crystalline Eye of Undravius to apply a cosmetic buff that changes the appearance of all other players and NPCs into Demons, while demons rain from above and green visual effects fill the sky around you.
Tips
Completing all rare Legion Archaeology finds also contributes toward the achievement A Keen Eye.
