Rodney, can you tell us where this is growing geographically? Looks possibly like something in the Apiaceae for starters. Can you show it again when those flower buds open?

Mmmm... 'deadly' poison? The degree of toxicity of S nigrum Is moot . It's toxic to a varying extents, yes, but you'll probably just get a stomach ache or be sick. Children would be worse affected. And it certainly isn't toxic to all animals. Black Nightshade is not the same plant as Deadly Nightshade. There are even strains grown for their fruit in some parts of the world.

Yep

Sort of looks like bind weed. Looks enough like it that I would try killing it the same way I did with the bind weed. Assuming you want to get rid of it, try this: find a bud vase, fill it half way with straight RoundUp (I used 42% strength), dip one tendril of the weed into the RU and leave it there. You might have to block up the bud vase to keep it from falling over. I don't know how long to let it sit like this, but when I did it for a few weeks, it killed the entire plant. You may have more than one plant, but bind weed grows from one central tap root. I killed 300 square feet of plant with one dip. This approach is very minimal impact even if you hate RoundUp. Only one plant gets treated.