I recently learned that nylon 11 (sometimes aka PA11) is made from castor oil, which (I also learned) is just the vegetable oil extracted from the castor bean.
Castor beans also contain high levels of the toxin ricin. As few as 5 castor beans, if chewed or mashed, can be dangerous for a human. The oil contains relatively little since it's a water-soluable toxin, but the leftover "oil cake" from manufacturing is pretty toxic and when used as fertilizer it's been accidentally eaten by animals.