Nao Igarashi with Blue Cat Cosplay Costume

Many people don't know what is cosplay? and i have the answer that i got from wikipedia.
Cosplay short for "costume play", is a type of performance art in which participants don costumes and accessories to represent a specific character or idea. Characters are often drawn from popular fiction in Japan, but recent trends have included American cartoons and science fiction.

Cosplay costume favorite sources include manga, anime, tokusatsu, comic books, graphic novels, video games, hentai and fantasy movies. Any entity from the real or virtual world that lends itself to dramatic interpretation may be taken up as a subject.

Inanimate objects are given anthropomorphic forms and it is not unusual to see genders switched, with women playing male roles and vice versa. There is also a subset of cosplayculture centered around sex appeal, with cosplayers specifically choosing characters that are known for their attractiveness and/or revealing