Cosplay costumes vary greatly and can range from simple themed clothing to highly detailed costumes. It is generally considered different from Halloween and Mardi Gras costume wear, as the intention is to replicate a specific character, rather than to reflect the culture and symbolism of a holiday event. As such, when in costume, some cosplayers often seek to adopt the affect, mannerisms, and body language of the characters they portray (with “out of character” breaks). The characters chosen to be cosplayed may be sourced from any movie, TV series, book, comic book, video game, or music band anime and manga characters. Some cosplayers even choose to cosplay an original character of their own design or a fusion of different genres (e.g. a steampunk version of a character).
Excerpt from: Cosplay @ Wikipedia.org