A 2006 segment on 'The View' helps explain how Trump and O'Donnell's bitter rivalry with one another first started.

O'Donnell riffed about Trump while on "The View," comparing him to the snake oil salesman portrayed on “Little House on the Prairie.”

If President Donald Trump, like Richard Nixon, kept an enemies list, one seemingly unlikely name would be right at the top — not a lawmaker or one of his predecessors, but the funny lady who tossed Koosh balls into the audience, and who speaks in frank and unadorned language about her disdain for him.