Pikashinygender is the shinygender variant of pikagender, other terms for this gender include pikashinychugender, pikachushinygender, shinypikagender(chu) & shinypikachugender.
The term appears to have been coined sometime before January 27th, 2019 by Tumblr user chibiusapositivity.
The original Pikagender flag was created by Tumblr user chibiusapositivity when the term was coined.
The Pikashinygender flag was created by Tumblr user "imoga-pride" on January 27th, 2019.
Two alternate pikagender flags appear to have been created by PUNKMUTT on September 24th 2020.
An alternate pikagender flag was created by Discord user Hal from Glitched Amethyst System, September 12th 2021. Its colors reflect the colors of Pikachu.