These female interpretations became popular and resulted in large amounts of fan art, as well as prompting art of gender-swaps of other male and female characters. This meant that female versions of all the game's male characters had to be created, as well as those of Street Fighter and SNK characters when SNK vs. Called the 'Midnight Bliss', it involved tossing a rose at a character to transform them into a helpless maiden and completely drain them of life energy. Prior to the creation of Rule 63, gender flipping was popularized in video games in the 1990s by the finishing move of Darkstalkers character Demitri Maximoff, a vampire.
It began to see general use in fandom communities as a term to refer to both fan-made and official gender flips of existing fictional characters. It is one of the 'Rules of the Internet' that began in 2006 as a Netiquette guide on 4chan and were eventually expanded upon by including deliberately mocking rules, of which Rule 63 is an example. Rule 63 is an Internet meme that states that, as a rule, 'for every given male character, there is a female version of that character' and vice versa. Cosplay of Lady Deadpool, a gender flipped alternate reality version of the superhero Deadpool
For a person who disrupts expected gender roles, see Gender bender.