Squash vine & flower?
We agree that this looks like a type of squash. An animal may carried a squash there or eaten squash and then 'deposited' the seed.
It is impossible to say which one. It may be something brand new-call it a mystery squash.
It may have been cross-pollinated with another squash/gourd/pumpkin. You can let it go and see what you get.
Here is our page on mystery squash, a.k.a. fruits not true to type: