Exploring Second Floor of Underground Cave

I was doing my Blue Fish hunt for Kielce Daniel quest when I stumbled across the green arrow to second floor UGC.  I'd only been there once before waaay back when I was a true noob and had just gotten my first Experts.  Back then all I saw was Black Fish upon entry and nearly got killed (92e gears, what do you expect?) so I left in a hurry.  Today I went in and explored.  Lo and behold, there were eggs like the ones in the clan raid Mad U.  So I went and smashed them and U came up, then rinse and repeat three times.  I only had two ranged characters since I went in with JosephDominic, Etienne, and Anastasia; had not anticipated doing this raid.  At the end there was a warp and a treasure box with my name on it.  I felt so special!  XD