A term for a type of lamp failure where the lamp gets unusually bright just before it dies, much like the death of a star. The filament may burn so hot that it melts and exits the envelope. The pressure differential creates a sound described like that of a gunshot. Glass reflectors, lenses and even gobos can be damaged or ruined. Other times, the envelope remains intact, and the only evidence is a discolored and broken filament. See this thread: http://www.controlbooth.com/forums/lighting/12040-epic-fail-why-fels-bad.html.