It grounds the static elictricity so you don't shock the crap out of yourself when you exit the car. Try the J.C.Whitney catalog...
Well , thats half the fun !!
Nothing like a fresh surprise after sliding across the seat
The thing I work on (at work) has 4 chains hanging from it on each corner to drop the static charge . Find a grounding strap , the braided style and cut one connector end off and bolt the other end to the chassis somewhere . Find a electrician and they may have a old one they will donate .