1) The thing that hangs down from a turkey's neck.
2) Also used to refer to the thing that hangs from an obese person's neck. Especially if a person was obese, lost weight, and has loose extra skin.
3) Can sometimes be used in reference to the male genetalia.
(3) female: "So, me and this guy were foolin around and his gollywhopper was huge, so I could only give him a helmet wash, but then he spiderman'd me!