It's not an acorn squash or a delicata squash. It's not a carnival squash. I have no idea what it is. I cooked it anyway, and I'll say this ... for me it was more trick than treat.
Update: It was stringy and fibrous, more like spaghetti squash in texture. Dumpling squash is like pudding. And, as Ruby said about her pie pumpkin, this was more savory than sweet. A little musky too. Maybe I just didn't have a good one - of the kind. Or maybe I've been spoiled with dumpling. Dumpling spoils.
This leftover one makes a nice seasonal paperweight.