lump after pooping

My little spider that I was trying to get to poop finally went, kinda. He has a lot of wet paper in his tub, but it wasn't color to it, and there were a couple of pebble looking poops, not a true poo. But he has always been that way. But I noticed a big lump close to his vent, it is kinda moveable, and is pretty noticeable. He looks very deflated back there now that he has gone. Does anyone know what this lump is or caused by?

http://i108.photobucket.com/albums/n...ps9a96424c.jpg
http://i108.photobucket.com/albums/n...ps76d033b7.jpg
http://i108.photobucket.com/albums/n...psc8d63b8e.jpg

Hi,

Sounds like he passed urates and liquid pee and still has a urate inside him.

I would just make sure he is well hydrated and wait for it to pass at this point.