Neptunegender is a xenogender which feels very large and fluid at first, but once you feel it or understand it more, it feels more solid and stable in its core. It is best described as being reminiscent of how Neptune is a gas giant with a solid ice and rock. Not to be confused by Neptugender.
History
Neptunegender was coined on or before September 7, 2015 by anonymous.
Flag
The flag was posted on that date by Deviantart user Pride-Flags on September 7, 2015.