I thought I had bought shishito pepper seeds and this grew. What is it?
First thing that jumped out were the 'spots'...this is Persicaria...same family as knotweed. This is called or at least its cousins, Lady's Thumb. Thus the thumb print in the middle of the leaf. This is a normal weed, edible, actually. Prettiest one I've ever seen...grin! Can you provide another picture, a close-up of one of the joints? It'd help identify the species/variety. Persicaria vulgaris