Ancient weeds began mimicking early crops again and again over the course of the agricultural revolution, as ancient farmers made similar mistakes in different places at different times.And it turns out, some of our closest plant friends today actually started out as uninvited guests that hid their true identity. From a certain evolutionary point of view, these plants tricked us into domesticating them. But this mimicry came with a dark side – along with some accidental plant friends emerged an accidental plant enemy, too.