A Zuke - O'- Lantern?

Looks like it could be a kabocha or a buttercup (i haven't grown either one personally so I haven't seen them while young, just going by shape). It's still immature, whatever it is, which is why it is easy to cut. Let them ripen on the plant at least until the skin is tough to dent with a thumbnail.

Rodney

concur: hard to tell with a green fruit. If a buttercup type it will have a pronounced blossom Scar. Several pumpkin varieties will have a similar appearance when immature. Several green round zucchini also look like your photo.

L'il Green Goblin

It doesn’t look like my Kabocha.

Thanks for all the comments.

I saw the pumpkin at a farmers market today, but the vendor didn't know the variety either.

The mystery continues.

If the vendor selling them didn't know what it was then it is likely just a random volunteer and no one here will ever be able to tell you what it is either. Like I said above it is immature still so it's basically equivalent to a summer squash at this point.

Rodney