American Beautyberry

Such an apt name, the plant is really normal except for the vibrantly purple berries that make it amazing beautiful. It's a Southern only plant and it's berries ripen in fall and are a source of food for birds and deet in the winter because they last so long.
It's a shrub, getting only up to 6 feet tall, with large leaves (5-10 inches). The leaves grow oppositely on the stems and are serrated, they can also have a little bit of a patchiness to the green color. The flowers are light green and show up in spring and they turn into the small, pea-sized, shiny, red-purple berries that clump tightly together around the stem by the leaves.
They are not known to be poisonous, in fact the berries apparently make nice jelly. Due to the nature of the berries they aren't good to eat raw, they don't taste very good and can cause mild stomach upset.
It's also a natural insect repellent. I'm not sure how, but that's what I read on Wikipedia... so it must be true. I later corroborated this in a book, so maybe it actually is true.