I made a mod for a skull with spine. will add the post how I did the spine. Skulls it seems you can get at any halloween shop. The spirit of halloween beer bong is a very good option. I made mine using foam instead. Let me get some pictures together and i will show them.
i bought a normal white skull prop from a halloween store. was about $5.
From walgreens i bought one of those "foam fun swords". They should be in the swimming or toy section. One for $5.99 or 3/$10. foam fun sword
This sword is hollow with a plastic dowel on the inside. Take the foam blade off the dowel.
As for the skull, use a drill, to drill a hole in the bottom of the skull about the thickness of a hanger
This are hollow with a plastic dowel on the inside. Take the foam blade off the dowel.
draw your lumbar spine on your foam blade like in the picture.
Take a wire clothes hanger and straighten it out. I took the plastic dowel that was in the sword and cut it into little pieces to add support in various places. I didn't use the whole plastic dowel because i wanted to be able to bend the spine in certain areas so I could wear on by back or on my chest. The wire hanger will give you that bend, but the plastic pieces will keep your pieces from sliding and moving out of alignment. Try to use your best judgement don't be afraid to hold it up to your chest or you cardboard dummy if you have one.
Use hot glue to attach the plastic dowels you cut up into about maybe 1/2" pieces. These again will slip into the inside of the foam using the factory made cuts that were already there. When you begin to slide them onto the hanger. put some masking tape at the top to keep them from falling off. The first part of the spine is the part with the most basic shape. You can use this spine i found off the internet as a reference for shaping the spine.
glue the dowel to the first piece of spine you insert so the top will always stay in place. This will be attached to the bottom of your skull.
keep slipping them in one by one until you get to the bottom. The length of the sword should be enough for one unless you want a spine of someone over 6' feet tall.
once you have them all on, you can glue the bottom into place. I didn't put the last bit of the spine where it attaches to the hip since i couldnt hold it and take the picture at the same time. You now have your spine. i will add some more pictures to this when I get home and continue to work on this. Unfortunately, I dont have any of my supplies since I am kinda at work at the moment. :S