a hairy, creepy guy who lures young drunk girls into dark corners with the intention of taking advantage. most of the time this happens at parties and the "lava monster" asks a drunk girl to accompany him to the bathroom or secluded corner. the term "lava monster" comes from the fact that everything the "monster" touches turns to "lava", meaning the girl wont be touched by any of the "lava monster's" friends because she is tainted
dude! did you hear about him busting a lava monster on that girl last night?
by mcmorris November 20, 2009