I have this vine that probably came in the potting soil, but I want to know what it is before I try and kill it. See picture for visual. Also the stems and underleaf are kind of prickly, but they are not sharp, the vine just grabs any clothing nearby and comes to a bitter end when we close the front door on it. It grew three feet in a day, and it is in the shade all day except for an hour in the afternoon. It definitely has a soft (not hardwood) center, and an almost square and flexible stem.
