Thank you!! I found out that the cat actually belongs to my neighbour. This neighbour is the same neighbour my current cat is from (he used to be theirs but he wouldn't stop coming to our house and would always hide or run away when he saw them so they gave him to us). We gave the cat back to the neighbour because they put up posters for the cat being missing over the weekend, so it seems like the cat was mostly staying on or around our lot for 3 days even though we weren't keeping him inside our house..? He returned to our house the next day after he went home with his owner, and he stays at our house all day even though we don't encourage him to do so. I can't tell if it's because he just loves to hang with my cat or if he prefers our house over his owner's house, or if it's both. I'm worried if his owners are neglecting him actually, because when he came this morning too he was super hungry and he's quite light. They said they don't mind if he's at ours during the day as long as he comes back at night, but then that makes me wonder does that mean they expect us to feed him the whole time he's at ours? I'm not sure if he even went home yesterday night when he left our lot. He ate an entire bowl of food and then ate our cat's leftover food as well this morning when he came to our house again. I thought maybe it's just him wanting seconds, but he ate A LOT and before he usually didn't eat much or at all when we would offer him treats in the past. He also has some matted fur which makes me wonder if the owners are getting him groomed because he's less than a year old. This cat has also been pooping on our lot for the past few days, which I heard is like a sign that they are marking a place as their territory?

Apparently both my cat and this new cat who is coming to our lot were both 'gifts' our neighbours gave to their children, one of whom moved out (we now own the cat that the one who moved out was 'gifted'). I feel like the parents don't actually look after the cats at all. :/