im freaking out. help me not freak out here plz.

OK so the mouse dropped dead like no lie. Dead after 1 round of battlefield 3. The lower half of body was In its water bowl why no idea the head was out the water bowl. ( only used water bowl cuz I can't find a good water source I can hang off my 10 gallon. Aside crime that. It died I placed it on the table forgot to toss it in the freezer Cuz wife asked me to do something. My wife has a name here aswell. Well I come back to it and their little dots crawling all over it inside this sealed zip locked bag . What the hell r those things!? Did my other mice get them? I ran an experiment and heated some water. Let the mouse sit in it while still in the bag. Come back 3 mind later now there's a lot of them wiggleing around in its fur and the bag itsself. Can anyone tell me what this is and what should I do
Plzz

Sounds like some kind of parasite. If you have other mice, you need to treat them all for mites/worms immediately, or you'll lose them too.

You cannot just cull and replace the mice. Because the new mice that you bring into your house will also get the mites, you have to kill them off. :(

Also, get a water bottle. It's not hard, just go to the pet store, there's got to be at least 10 bottles for you to choose from, that will work in a 10 gallon tank.