Vollym’s Battle Pit, Gendarran Fields
If a Bloodstone-Crazed Arcodus spawns in the middle of the first part of Vollym’s challenge where you fight all of the caged animals, and you kill all of the caged animals before killing the Arcodus, the end of that part/beginning of part 2 where you fight Vollym himself causes the Arcodus to despawn without rewarding anyone anything (for the Arcodus). The Arcodus’s event marker remains for a minute or so after it despawns and then disappears as well.