A slightly bigger than normal, angry, adult, male doctor. Wherever the doctor naturally live, except it's only the size of a football field. The cheeseburgers can be whatever kind you want, but no secret sauce. They have to fight this doctor with their own selves. They may use the torn buns and maimed toppings of fallen friends as weapons against the doctor.
I think you could get like ninety of them to surround the doctor, then scare and confuse it while the rest split up. From the group of ten, two could work on poking the doctors eyes out and then climbing on it wrap their onion rings around its neck to choke it, while the last eight burgers, hold down its limbs. Two per arm and leg