Dog found disgusting creature in the woods!

Our dog usually runs free in the woods while we take a walk. Sometimes she runs away for a minute but loyal as she is, she always returns.
Before, she’ve taken a few birds and even a baby rabit and proudly given it to us, as dogs do I guess? But this time she came with something disgusting in her mouth…
Below you’ll see some nasty images of the “thing”.

This is what she found:

And another more zoomed in picture:

What the fuck is that? Can you believe she came carrying that in her mouth more proud than ever!
And I mean, it’s not that small compared to her so she really had to use her muscles.
I think it’s a moose miscarriage? Since under the big white membrane, there’s a huge head compared to the size of the rest of the body. (Or maby it’s a werewolf? Haha)

I can’t believe she had that thing in her mouth… ewwww.
What should I do with it?

The dogs name is Tess and she’s a 7 year old golden retriever 🙂