Galaxy Accident

The Refusians referred to the "giant solar flare" which caused them to lose their physical forms as a Galaxy Accident. (TV: The Ark)

Behind the scenes
Although likely a line-flub for "galactic accident", the term "Galaxy Accident" was used with full intentionality and capital letters in Sonnenblumen which saw the beings of light's Dawn's version of the Sun to be "shattered into its light and its heat by a rogue wave of dimensional pressure", causing a similar effect to the Refusians' dematerialisation.