Unique Pumpkin Harvest

We harvested our pumpkins and interestingly only one looks like a pumpkin. These were the fruit of the two pumpkin plants. I suspect some cross pollination, maybe from the cucumbers or the peas. These pumpkins were grown from 4th generation seeds. We started with seeds from a pumpkin 4 years ago, and replanted its seeds when it faded. That has been repeated each year.