it's is nothing, just a collection of sounds and letters that were interesting at the time.
there is no hidden meaning, possibly....
what it is, though, is the user name nerver taken, i always know when i have signed up for a site, because there is only one fugmulch. who would want more? this way i don't have to remember 1000 user names, or if i am sadistickitty0121 or insertfunnysupposedlyendearingusernamehere or even joeuser8884829837237.