I'd say it looks like tapeworms. If it is segmented then it's definitely tapes. It looks like some feces there (the dried powder looking stuff). If that is, then its good they came out the back end...just good that they came out. Best thing to do is take some fresh feces to a vet and have a fecal float done for eggs (if they aren't tapes). Tapes pass eggs in little segments that look kinda like rice, so if you see something like that, get them to the vet to be id'd. Tapeworms do have to go thru in intermediate host....i.e. fleas...it's possible ot get from eating a mouse with fleas.