noun. An assmunch of great proportions.
Real citation: "How many names does megabuttmunch have to use before he figures out how to spell his own name?"
(May 23, 2006, http://www.coder.com/creations/tale//tales/cgi-bin/tale.pl.cgi?PAGE=45794&STORYDIR=Grand_Testing_Tale)
Made-up citation: "Though I'm a megabuttmunch in most fields and endeavors, I've become the Tiger Woods of Connect Four."