This happens every summer.
I swear to god, my cat isn't ill, and I'm not abusing him. Look at his beautiful face:
This is a feline of beauty. It's just a tad, well, touched. His name is Cooper. Those of you who read J&J will recall that this is the one of our three cats who chose to live in our ceiling for a few weeks a few years back. He's a smart guy, and gorgeous and sweet (well, except to Robert the Dog), but, well, we rescued him as a feral kitten from the coyotes and rattlesnakes of rural New Mexico, and he's never been just entirely right in the head. One of the results of this is that he really isn't so much with the grooming. Like, at all. And every summer he gets like this. I brush him and brush him - okay, maybe not just exactly as assiduously as I might, but still - and still winds up so hopelessly matted that he looks like he's wearing a felt jacket. It's horrible. So I trim him, bit by bit, a spot at a time until he freaks out and I have to stop. And by the end of the summer he looks like the Montauk Monster. Poor buddy.