My friend is having a problem with her 13 year old female cat. One day she just walked out into her living room and her cat attacked her, she was growling, hissing and biting her leg, she was out for blood. i have never seen this cat so aggressive. now this has happen 4 times in the past month, and she goes after the same person every time and when she cant get to that person she attacks the next closest person. for the hole 13 years she has had this cat it has never done anything like this. she is an inside cat. What could be causing her to act like this, if the cat keeps it up they are going to have to get rid of her, and they don't have money to take her to the vet to get her checked out, is this somthing easy to fix? or is there somthing wrong with her?