Hmm. I'm not sure. At this point I'm thinking my volunteer is probably a delicata squash. I had this idea while I was in the squash section at G-Life.

Delicata seems to vary in size, shape and texture, so yours might be one too. Mine definitely has the ribbedness of a delicata but yours has more of the broken line markings.

Also, it looks like yours is growing more vine like. Delicatas do come in bush and vine varieties. Mine is definitely more bush like.

Mine is definitely a vine and I'm 99% certain it's a squash. I think it's probably a spaghetti squash.