Popularized at a 1942 state fair, it's a frankfurter dipped in batter & deep fried
[DOC] [TLE] Corn dog - Dictionnaires [PAR] A US patent filed in 1927, granted in 1929, for a Combined Dipping, Cooking, 
and Article ... dog vendors lay claim that credit for the invention and/or 
popularization of the corn dog.