You Tell Me and We'll both know....

This is the vine that has taken over the tree or bush between me and my neighbor's house. He likes to plant things here and there and then let it grow wild. This vine has taken over part of the fence and every week I'm trimming this thing back. I hate it. So tell me folks... What is it?

Here is a picture of the fruit or vegetable the vine produces. It's usually a little bigger than what this one is but I chopped the bush and the vine back yesterday because I don't like this crap growing on my side of the yard.

Here is what the thing looks like cut open. To the touch it feels spongy.

So tell me what you think. What is it?