Skullgender is a xenogender connected to skulls/skeletons, either human or animal. This can be a kingender but not necessarily. It was coined by Twitter user @xenobabie on December 6th, 2020.[1]
Flag
The flag was created alongside the term, on December 6th, 2020. It is composed of six stripes in a monochrome gradient, with dark grey at the top, going down to lighter grey at the bottom. Overlaid is a dark, translucent image of a skull and crossbones.