Hollywood Society Girls in Catfight!

The parking lot between Les Deux and Element has become the new Thunderdome -- with fights breaking out all the time! What's in their cocktails?!

TMZ spotted a couple of hot messes screaming up a s**tstorm last night, and while we have no idea what the fight was about, it's damn fun to watch!

The highlight -- one train wreck stealing the other's purse and dumping the contents all over the concrete. "Gimme dis wallet!"