a) Any person who has an extreme desire to only associate with Asian or Asian descent people -- socially, sexually, etc.
b) a fetish for a certain thing, things/anything Asian.
a) "What's with him/her only wanting to be with Asians? Turned into a real rice monster."
b) "Man, he's/she's totally hooked on that (fill in term such as anime, japanamation, etc. here). Turned into a real rice monster."
Joke among fans of X Japan and/or drummer and pianist Yoshiki Hayashi. In a blog entry, Yoshiki, who at the time had been on a strict rice diet, claimed to have a nightmare about "the RICE MONSTER" attacking him.
The joke has no relation to either of the other two definitions, and most fans of Yoshiki telling the joke would be offended at either of them.
"The day before yesterday, in the airplane on the way to Japan, I had a really weird dream….. I almost….. Well, I think I screamed!! The flight attendant came to me and said "Are you OK? ....." Then I said "THE RICE MONSTER IS TRYING TO EAT ME!!!"….. And she said……. "WHAT????" and I said……mmmm……ah……. "Never mind……ah….. Could I have a glass of Champagne and Caviar please?"
……. OH MY GOD!!!..... "I am so embarrassed"….. I've been doing a "special diet" and training, in order for me to play drums even harder….. Since then "THE RICE MONSTER" has been showing up in my dreams. Ha ha ha ha ha!!!"
- from a 2007 blog by Yoshiki on Myspace, and the origin of the term's usage