It was found on a hillside behind my house. The stem has small thorns and the fruit look like tiny watermelon. Thanks for your help!
Jill, this is the fruit of Solanum carolinense, the Horse nettle, a weedy native. It is in the same family as eggplants and tomato, Solanaceae. Do NOT eat the fruit – I’m not sure just how toxic the fruits are, but they could be quite dangerous.
–Steve Hill, Botanist, SCNPS