Referring to the fictional character, Michael J. "Crocodile" Dundee, of the 1986 Australian comedy film "Crocodile Dundee". The title is used to compare a person to Crocodile Dundee due to their involvement and aquisition of alligator and/or crocodile leather.
From the song "Throw Some D's" by Rich Boy (Maurice Richards):
"Candy paint, Gator skin seats call me Dun Dee
Up in your hood I'm the one that you wanna be"
when you had way too many jack and cokes. incapable of rational thought. When you are classified as retarted.
I am DUN DEE! Give me another beer.