Research "cannonball gourd" and see if it matches. Where did the plant come from? A volunteer, direct seeded, gifted to you?

heh, pick it and try eating it. If it is icky for it, probably not a summer squash. Might be a winter squash or gourd then.

I did not plant any gourds. I planted acorn squash, but those didn't germinate. In that spot I've planted cucumbers, acorn squash, peas and cantaloupe. The first seeding it was too cold and wet. Nothing grew. Replanted cucumbers and peas. I had pumpkins last year and didn't want more of those. Gourds are cute, but I don't want to grow them! Thanks for your help.

Cucurbits do mix rather freely, so it could be something new, or could have been mislabeled seed. Both such things happen.