Poop or Regurge?

So I was cleaning out Sam's cage today and I found two 'poops', one normal looking one and one slightly irregular one. (He usually gets one mice per feeding, but last time I gave him 2) The weird looking poop was pretty large, and normal color, but the weird thing was, was that there was a foot and a tail still attatched. However, these were also the brownish color, suggesting to me that they had already been digested, at least partially. Also, the aspen around the stuff was yellow, which makes me think it was urine. I guess my question is, does snake poo sometimes leave behind mouse parts like tails? This doesn't look like any regurge pictures I've seen on the forums, I can post a pic if needed. Thanks!