<human>: Can you condense the text into three sentences or less?

I'm watching my friend's cat this week and he has attacked my legs several times. He managed to latch onto my left calf pretty good a few days ago and now I have some bruising around the little teeth marks. He's never been friendly, but he wasn't so aggressive when I watched him before. There used to be two, both unfriendly and aggressive, especially with strangers. The other cat had kidney failure and was put down a few months ago. The remaining cat started to be more friendly now that his friend is gone, but had taken to biting as I walk around the house to feed him, clean the box, etc. Pretty sure he's fixed but not declawed. I know better than to be aggressive back and usually just clap loudly and/or say "no!" sternly, but this only works temporarily, and he'll bite again after a few minutes. Is there some way I can show him I'm in charge or teach him not to bite, or is this something I'll just have to deal with when I watch him? I'm not exactly a stranger as this is a good friend's cat. Know any tricks to get me through the week? So far I'm just wearing pants and hoping for the best, but it's a hot summer. Internet and other Reddit post searches have proved unhelpful. Please help! Happy to answer questions and give more details if necessary. I'm a work now, but will try to stick around. After 5 I'll be around more. Thanks!
<bot>: My friend's cat is a biter and I want to know the best way to avoid bites while I watch him.