No, not the reproductive system of pet mice, but something that my vet fished out of my dog's (aged 2) gut today.
She was out of sorts since Saturday - not eating, sleeping, not pooing, trying to be sick etc. I took her to the vet yesterday thinking that perhaps she might be constipated (web-vet that I am). There was no sign of constipation, but she was very dehydrated and her heartrate was worryingly high.
The vet didn't know what the problem was yesterday, so kept her in in order to hydrate her and see if that improved her condition. She was still poorly this morning, so they did an x-ray and saw a metallic object that was fuzzy round the edges. When they opened her up, they found a mouseball. No idea how she could have got it as we haven't had balled mice for years - she must have dug it up.
She should be fine now