A atrata would be nice but I imagine A vulgaris is more likely if it just popped up as a self sower.

It gets a lot of shade.

Nobody? It's grown but still looks about the same, except those little round bumps mid-stem are black and a second black group has formed below it.

2 of the 3 photos have the leaves of something else in them, a Verbena or similar. There's only 1 photo with only the true leaves.This photo shows the leaves.This is my Mirabilis nyctaginea, and the upper leaves are very similar to the OP's photo, perhaps slightly wider, but same shape and look.This is a clear photo of Mirabilis nyctaginea seed pods. Do these look like what you saw Dandy? There is one more possibility, Mirabilis albida, also occurs in Minnesota and has slightly different leaves. You will have to compare your plant with those 2 species for an ID. 😵🤣 Impossible to call with these photos. There is 1 more native to Minnesota, Mirabilis linearis, but it has longer, very narrow leaves. I'm pretty sure it's a Mirabilis 😬🥺 https://youtu.be/IPxSNRY1c8A