Bright red blood, fifty cent clump of clots with a sac, grey tissue?

So many questions?: Something you found on the street? Passed from your rectum? Your vagina? Were you pregnant? We need a few more details here.

Possible Miscarriage: I am assuming you are referring to clots of blood with a gray sac that you have passed from your vagina. Have you missed a period recently? This could very well be a miscarriage happening. Otherwise it could be that you are experiencing a very heavy bleed. As the other doctor said we need a bit more information before we can help you with your concern.

Miscarriage?: I do not see your age or sex in question, and you did not specify where this came from, unfortunately however, it sounds consistent with a miscarriage. You should follow up with your Gyn in the next couple of days, particularly if this was not expected or if the bleeding continues.