Gulus Realm Burst

Gulus Realm Burst (グルスレルムバースト, Gurusu Rerumu Bāsuto), also known as GRB, is an infection originating in Regulusmon's body, that increases a Digimon's survival instincts and fighting power. It is said that Digimon infected with "GRB Factor" have their personalities altered and become frenzied. The concept and terminology is a reference to, flashes of gamma rays that are the most energetic and luminous electromagnetic events in the universe.