Devil Dog is a nickname for a United States Marine coined during World War I.
They call the American scrappers "teufel hunden," which, in English, means "devil dogs.
"[10][11][12][13]The American press immediately seized upon the new term, and it was used on a Marine Corps recruiting poster by Charles Buckles Falls in July 1918, showing an American bulldog chasing a German dachshund wearing a pickelhaube.
"[4] Further, when asked about the term by Stars and Stripes, Lt. Col. Heiner Bröckermann of the German Military History Research Institute said that he had "never heard anyone using the word 'Teufelshund' or 'Teufelshunde' in Germany.
"[4] Nevertheless, "Devil Dog" has become firmly entrenched in the lore of the United States Marine Corps.