Cosplayer are the natural spin off of Anime/Comic conventions, even outside
of Japan. Even so, there are the people in Japan who can‚t get satisfied merely wearing anime clothes. They need to get inside of the anime-character's body.(*1) They are known as "Dollers" As well as this type of play is called “Kigurumi”
(*2). And this language is getting recognized by fetishists all over the
world right now.

Dollars make a character costume and a face mask. They don’t show even an inch of their skin to the outside world. Since some dollers are covering
their face in many layer of cloth, it’s a very risky sort of play, like
bondage. Dollers may be seen as merely as crossdressers, but the resulting
visual punch is way stranger than a transvestite, or any other cross gender category.
The lines being crossed are 2-D to 3-D, kid to adult, and fantasy-real.

Some of the dollers claim that their mask is not there to hide their face.
They are not pretending their own existence. The person who is inside of
the character is there to actualize the character's motion and thought. The mask is the character's head and the tights are their skin. The feeling is similar to playing a simulation video game.

Unlike cosplayers, anime character dollers are not wearing a costume.
Rather, they are physically and psychically entering a character.

If anime itself has become a dominant mode of expression in Japanese pop culture, then anime dollers are a true example of subculture of Japan at this moment.

-J.Tack 
 

Footnotes

*1: Although there are many mask-play lovers in out side of Japan, too...
http://www.maskon.com/Maskon/Maskon%202003/maskon2003-1.htm

*2: Kigurumi
http://www.pettipond.com/laterimages/cosplay/kigurumi/
 

Related link

The original Doller who started the phenomenon: http://www.doll-house.jp/

English site from Japan: http://www.geocities.com/WestHollywood/Cafe/5237/