Rot Lop Fan was created by Alan Moore and is one of the most unusual members of the Green Lantern Corps. He initially appeared in Tales of the Green Lantern Corps Annual #3 in a story entitled "In Blackest Night" wherein Katma Tui recruits Fan as the Green Lantern of his sector. Having evolved on a planet with no light, Fan's species have no eyesight and no concept of color, so Katma Tui has difficulty explaining the concept of the Corps. Tui reshapes the lantern into a bell and refers to the Green Lantern Corps as the "F-Sharp Bell Corps" instead.
Source: The Daily Blam!