Aww! I'm sorry. If it weren't any type of bite another option would be leukemia. My Mamaw's cat Jasper out of nowhere just couldn't move and it was devastating to watch him try to move because it appeared that his back legs were...broken and contorted. My aunt took him to the vet and they told her that he had leukemia! It was a sudden tragedy but God she's got 5 pets to occupy her now (2 of which you saw in the picture of me and Daniel at her house. She's also got a tropical bird, a cockatiel, and a guinea pig). 😂