I couldn't post the photos, but I feel it is quite unlike anything else I've come across locally, hoping a description helps!

It looks similar to a watermelon plant, very similar leaves, growth form is more like a "bush" squash (though still young!)

All stems are thorny as anything.

Flowers are solid yellow, and are shaped just like a potato/eggplant. I'm 99% sure it is from the solanaceae family. Free flowering, it was flowering just weeks after sprouting.

The 'weed' sprouted out of a pile of fill, excavated anywhere up to 15' deep in a huge hole. Or bird pooped it on the pile of fill!!!

Any ideas? Maybe some strange crop? It isn't in either of my native plant books, and I am in the boonies, so I'm pretty sure it is not native, at least not locally!

THANKS!!