Hubbard's are usually bluish & bumpy & hard as a brick.
Those look like mutant zucchini -- power plant near by???
Probably some form of a gourd. We planted normal orange pumpkins one year, but the next year we had funky shaped gourds with warts on the surface, then some green pumpkins that look exactly like what you have there, & a bunch of other types. We were told that there are different genes in the seeds after the first generation ...... but after that, you'll never know what your gonna get........ You only get orange if you bought the seeds in a store. I have no idea how they sift through the weird stuff & get the normal orange pumpkins.