Black Swallow-wort: Pull it if you see it. These plants will start seeding soon. It’s an invasive non-native plant that can cause problems for for monarch butterflies and crowd out native plants.
To learn more and be able to identify it check out this article: https://www.somervillegardenclub.org/2017/10/black-swallow-wort-pod-patrol/?fbclid=IwAR2RCHMtqSxObVTYu-9oeV3k8tuGB_od40099h6yJmQLBWvZi0p5vStLuJQ