On NPR today there was a guy who works to get declassified stuff that shouldn’t be classified anymore. For example, Elvis once met with Nixon on the spur of the moment, just showing up at the front gate asking to see him, and asked to be made into an honorary undercover narcotics agent. They chatted, he got it, gave a gift to Nixon (a pistol!) and that was the end of it. This is classified information by default, and stayed that way because no-one ever asked for it to be declassified.
Acoustic Kitty was another project he got declassified. The project involved embedding microphones under the skin of cats, and then sending them in to curl up near (or in the lap of) The Target. They’d tried dogs and stuff, but cats are more likely to stay in one place and sit still.
So they got the plan all put together, got a cat, trained it, put the microphone in, and took it to a park in D.C. They marked the target and turned the cat loose. It started to move in.
And then got hit by a taxi.
End of project.