Yeah that's gotta hurt.
People have gone to hospital because of that....
Never had a cat stab me in the back but I had one scratch my 'member'. I just steped out of the shower and my cat, a kitten at the time, thought it was just another toy for it to pounce at.
We've got a bleeder!
Wow. I feel like I've just got to say it for the benefit of all: there are some things one should keep away for cats. May a word to the wise be sufficient.
Cats are good for the busy person who has little time to care for a pet, as you can throw extra food and water in dishes, fill up the litter box and leave for a week. When you come back, your cat will look up at you from the back of the couch like, 'Where the hell have you been?' and go back to sleep. They are the perfect pet for someone who lives alone, works long hours, has a difficult or variable schedule, etc. because cat, unlike dogs, don't die of loneliness. Cats can and will entertain themselves, and if you aren't meeting their low, low emotional needs, they'll just leave, 'cause if there's one thing you can be sure of, it's that your cat doesn't love you.
I would not actually leave a cat for days on end alone unless you have other cats. They are not really consummate loners, they are descended from small rodent hunting pack animals. The thing is their hunting strategy is to split up from the pride and hunt alone, returning to the pride at the end of their hunt. So they are used to being alone some of the time (unlike Dogs which hate to be alone ever) but not for prolonged periods.
If they got lucky and caught anything they'd drag much of the carcass back to the rest of the pride to share. In part because they were likely related to many of the members of the pride and in part because the last half of a kill after you have eaten your fill does not have much value to you but has a lot of value to those who have not been successful in their hunting. You gain later when your hunting has failed but still get something to eat if another cat has made a kill. In the wild this can be a life savour, providing you with enough strength to try your luck again tomorrow. Very important since hunting animals fail much more often then they succeed.
This is one of the reasons cats will drag in half dead birds and mice and such and present them to you as a present. Its just chipping in - after all your a phenominal hunter - you probably leave every day and you always have food.
Any way don't leave your cat alone for too long, it is a social animal - just one that expects its pack mates to leave for many hours on a regular basis.