I was wondering this too. How far along were you? I was 9 weeks, sac/fetus had shrunk to 6 weeks. I started out with lots of black clots/tissues for 3 days, it subsided, and then suddenly a huge gush of blood, went upstairs, bled like crazy, and then suddenly a large red sac (about the size of two full thumbs put together) came out into the toilet, that was the sac/fetus.
It honestly looked like a veiny/bloody tube (sorry but that's the best I can describe). I thought I would be grossed out but I picked it up and wrapped it in a nice baby swaddle.