It's a pretty picture, but I don't think that shutter speed (or multiple exposures of a long shutter speed) type ghosts are really transparency. Too bad you couldn't have known that the shutter speed challenge was coming, this would be a very strong entry there, but it doesn't meet my definition of this challenge.
Interesting setup. I'd be curious to know how you did this after the challenge is over. I find that bit of green around the skull's teeth distracting, and for me, I think cropping out the partial pumpkin at the top would work better.
I'm not sure why I want pumpkins transposed over a skull. The two have little to do with each other (except simply being two halloween icons). Technicals aren't bad.