So out of nowhere my bathtub is clogged shut. i pulled the stopper out and clogged the hold with a wet towel and plunged away to no avail. Tried to snake it and it seems to get stuck on something solid and never go into the u shape part of the pipe. I don't know what could be down there because my stopper assembly came out completely as it should have. I know it's not clogged with hair or anything. And this is not a slow drain, it's completely stopped up. I have no clue what to do other than go under my house and cut the pipe open to see what's causing the clog. Any ideas what else I cou try or what may be causing this?? Thanks...