Officially introduced during the Tiger Lily case, O’Copper was a stock Gould style Irish Patrolman who helped rescue Junior and Frizzletop who were tied up in a sinking boat. Dennis then joined Tracy in tracking down Tiger Lily and remained with the famous detective to help him during the Pruneface case.
O’Copper did not return to the strip until he made a brief appearance in 2012 as the husband of Frizzletop. Dennis is still in uniform and still serves as a highway police officer. The Irish cop appeared again in 2014 during the car chase and gun battle with of Silver and Sprocket Nitrate as they escaped the police with their famous car. Dennis was on hand to give Tracy and Sam a hand out of their vehicle when they were shot off the road.