One or two wild things usually pop up from our compost that we put throughout the gardens. Sometimes it's a tomato, sometimes it's a flower, and sometimes it's a mystery for a while. When I saw the greens on this plant I was hoping that it was going to be a pumpkin, but it turned out to be an ornamental gourd. (emphasis on mental.) The runners on this fellah must be 25 feet long, so I have been calling it (cue the dramatic music here) Gourd-zilla. Run wild, run free Gourd-zilla. Just do your thing.
Postscript: We harvested about a dozen of these yellow and green gourds,
and six of the plain yellow ones that look sort of like pears..