U.S. Marine here..... a challenge coin started back in the day to sorta settle bar tabs, the way it was explained to me when i was a young boot in the Corps. .... 2 Marines, soldiers, sailors or airmen etc.... go to a bar... now lets say they bet on who pays for the drinks... 1st Marine throws down a challenge coin from General Zinny .... the second Marine now has to throw down a coin that TRUMPS that particular rank or person.... if the other Marine drops lets say.. POTUS coin.... he wins free beer....get it? In Marine Corps. lore of challenge coins R. Lee Ermy ( which i have ) coin trumps just about every coin.... i haven't lost yet with it ....usually you recieve a coin when you impress or meet the particular person of notoriety....ive seen Mattis coins and they win alot too ...( also own one of those but since tossed it due to his disrespect of Trump.... didnt meet him it was just given to me) ..... never seen a Trump challenge coin, nor have any of my fellow jarheads. But yes! I did meet R. Lee Ermy in Phoenix AZ in 04 and he gave me a coin. Been drinking for free off of it ever since!