Slang for when someone loses there focus or ends up failing to do what the had set out to do.
When I failed my chemistrytest, I had lost the plot.
I was telling my friend a funny story, but then I lost the plot and started talking about my grandmother’s brownie recipe.
Brought to public attention by Bob Woodward and Carl Bernstein in the book on the fall of Richard Nixon, All The President’s Men, ratfucker was Nixon’s term for a political operative who sows chaos among opponents; an agent provocateur. It is thought to have originated among campus political rivalries at USC, and seems to have some usage in the US military.
Along with Nixon’s other ratfuckers, Roger Stone caused fights at otherwise peaceful Democratic Party protests to generate a false narrative that the Democrats were violent and dangerous.