Rum Ham originated in Season 7 Episode 2, "The Gang Goes to the Jersey Shore". The ham originated when Frank wanted to get drunk as well as eat ham on the beach, and was involved in a Castaway-esque series of events.
The ham appears to be a normal ham, just soaked in rum as well as having two pineapple rings for eyes, and a red cherry for a nose, again continuing the 'Wilson' in Castaway themes.
Since its appearance, the ham on hand has appeared in many episodes, such as Season 10 Episode 6, "The Gang Misses the Boat", and Season 11 Episode 2, "Frank Falls Out the Window".
The ham has gained a significant cult following, with multiple people recreating the famed ham on cooking websites, as well as fanfiction peices of art being drawn of the ham.
Happy now, Caleb?