A nickname for a Member of any one of the Mormon sects LDS, FLDS or RLDS.
The name comes from the belief that God lives on a heavenly Body (a planet... or star!) called Kolob.
The reference is from
Joseph Smith Junior's writings called 'The Book Of Abraham, which is part of the Mormon canon of scripture
The modern Mormon church doesn't mention Kolob much as the
whole thing is a source of
embarrassment, hence the nickname Kolobian is quite hurtful to mainstream mormons