OG Maco, the Atlanta rapper behind the viral hit "U Guessed It", is going at the featured artist on the aforementioned track (as well as collaborator on him Give 'Em Hell project) on his latest track bluntly (and harshly) titled "Fat F**k". Pretty cruel. Apparently Maco and Key! still work on a professional level but are at odds on a personal level. Interesting. Listen to the supposed Key! diss from OG Maco after the jump.