Illusogender
Illusogender is a gender identity in which one understands their gender, but has a feeling of 'fakeness' in regard to it. The feeling of fakeness may be considered a part of one's gender or an outside force. Subsets include illusoboy, illusogirl, and illusenby.
Flag
The illusogender flag was designed by pride-color-schemes on Tumblr and posted on September 27th, 2015. The figure at the center of the flag is inspired by the "duck or rabbit" illusion.
Resources
https://lgbta.wikia.org/wiki/Illusogender
https://www.deviantart.com/pride-flags/art/Illusogirl-1-562944224
https://www.deviantart.com/pride-flags/art/Illusoboy-1-562944251