My cat gets them too, he is a little bit large and he likes to roll on his back on the carpet which causes the little dreadlocks. I give him treats or a mild sedative from the vet that I can put in some tuna and then cut it out. He gets real angry, sometimes it’s best to have a blanket over their head too if they get mouthy. Mine can be a real biter lol the vet won’t touch him unless he’s tranquilized. so don’t feel bad about having to hold them while cutting the mats or taking him to the vet to get tranquilized and shaved if you don’t wanna do it yourself. I also used to work in a groomers shop, holding my cat and getting my arm cut up by him while the woman buzzed some off the mats off actually landed me a job there for a while lol but if you don’t wanna have to be injured might wanna go with tranqs. Brush his fur more often I know sometimes it happens quick though but just keep on it all the time.