A mysterious Digimon that supposedly Digivolves via evil, dark energy concentrated to extreme levels. During research into Digimon that can secrete the so-called GRB Contagion, simulations of injecting enormous amounts of the contagion into such a Digimon resulted in this "theoretically" possible Digivolution. The simulation was repeated hundreds of times. As each test confirmed that the Digivolution would result in this Digimon, researchers theorize that, under suitable conditions, Arcturusmon could actually manifest in the Digital World. While its mannerisms and behavior are unknown, the amount of dark energy measured in the simulations far surpasses that of all identified Digimon, which indicates that the emergence of Arcturusmon could hypothetically result in a Digital Hazard that would reshape the face of the Digital World. Arcturusmon's supposed modes of attack include Black Death, where the target is stabbed with an arm drill and injected with the corrosive GRB contagion, and Dark Confession, which coats both of its drills with large amounts of GRB contagion, rapidly spins them to condense the secretions to inordinate concentrations, and then launches it forth as a ranged attack.