A variation of the word damn.
Used as an expletive to express anger, annoyance, disgust, etc.
Also can be used to exclaim a point.
“I dropped my beer, DangDog”
“DangDog, get out of the kitchen!”
“Quit following me around the house. DangDog!”
“I just won the lottery, DangDog!”
“That band was awesome, DangDog!”