Variation of a well-known McDonald's sandwich, which, as a variation, replaces the usual tomato with rice. Thus the name.

Although a bit weird to eat (the rice often keeps falling off the sandwich), the result is deemed to be certainly original.

When McDonald's representatives were inquired about the origins of such a particular dish, they refused to make any comments.

MCDLR: Accronym of "Me Cago De La Risa" , an Uruguayan translation of the so called LMAO (Laughing My As* off)
This expresion became popular in the web forums worldwide, as an effective way to mean a high level of laughing due to a funny action, or a joke.