Internet slang for when something was likable, but turned out to be bad. It refers to the time Waffle House debuted their new duck flavored milkshake, which everyone loved, but then everyone found out they made it by putting an entire unclean duck in a Vita-mix.
“Such a bummer, when a trusted corporation everyone loves suddenly turns into a milkshakeduck.”
Traditionally, a Mud Duck, as colloquially known to the White community, is a white female who dates african american men. In hunting, a mud duck is a species of duck who are known to congregate in ponds and eat bugs from the muck, often grey or black in color; distinct from the grander Mallard or Wood duck species, Mud Ducks are usually easy to find and their meat is of subpar quality.