Jack is cool, but his burgers suck. And how do we really know it's always the same Jack under that bobble-head of his? Has anyone fingerprinted that dude, lately? He could have a hundred imposters running around, stealing his paychecks and sullying his public image with bizarre antics!
If you're feeling particularly festive, you could finish off the rest of the outfit with a couple of gourds and a cob of indian corn hung way down low. Call yourself the Harvest God or something, and run through a couple of McDonald's and Burger Kings late at night, screaming, "Booga, booga, booga!" Be sure to have someone tape it all, including your subsequent tire-squealing escape in a Fox-bodied Mustang, and post the full video on here, afterwards.
Another idea: Use a big one of those plastic kids' candy pumpkin thingies, cut out a hole in the bottom big enough to put your head into, cut out the eyes and glue in some of that thin black see-through mesh material, then throw a big straw hat on top to cover the top hole and ... umm ... I dunno, rob some dirty old hippie of their worn-out denim clothes, stuff some straw here and there in the pockets and sleeves, and then maybe go as a scarecrow...?
Rent Sleepy Hollow, if that's the kind of pumpkin-head you're leaning towards, and maybe take some styling tips from that dude's getup. Or, better still, the old Pumpkinhead flick with Lance Hendrickson, perhaps? Although that one might be a bit tough to pull off without the aid of a special-effects team on hand...