I had planted a pack of very-generically named "Wildflower" Seeds a few months ago, and these sprouted. I have never seen anything like them. The stems are very thick, the mauve colored flowers are fuzzy and droopy, and the plant itself currently stands at my hips and is still growing taller. I absolutely love this funky addition to my garden, but I sure would love to know what the heck it is. If someome could help me to identify it, I would greatly appreciate it!
It's an amaranth, possibly Amaranthus caudatus (also called Love-lies-bleeding), although the flowers should be a bright red and the leaves look a little off. Its seeds are edible and can be made into flour. The plant can reach 6 ft, and the flowers dry well and retain their color.
Note that Amaranthus is also the genus for Pigweed, so if you let it go to seed you will probably always have it.