Bittermelons look like what hedgehogs would be if they fell under a wizard's spell and became vegetables.
Once in a great while I like bittermelon Chinese-style with furu, fermented tofu. My Filipino neighbor loves bittermelon. Birds love his ripe bittermelon fruit and scatter the seeds, so occasionally I find vines growing in the middle of the lawn, which I mow anyway. However, now there's a bittermelon vine growing on the fence between me and my other Filipino neighbor. I'm sure neither of us planted it, but I'm not entirely sure if he's eating from it. He hasn't sprayed it, and usually he sprays the fenceline. It's actually my fence, so I guess I could just rip the vine out. But I don't want to spoil my neighbor's enjoyment, that is, in case he is in fact enjoying it. I suppose I could ask him, but he never answers the door when I go over.
So the vine just grows. Is it a weed? Some people would say if someone has found use for a plant, it isn't a weed. So I guess it isn't, because for me right now it serves as a reason to get to know my neighbor a bit better.