my initial opinion is that it doesnt exist. if tool puts the energy into writing a song and its good they will make sure its heard, if its not good they will make sure its not heard.

that said they do have a couple "hidden" songs so its not out of the realm of possibility.
ide say that that quote would be a hint as to how to find such a song.

ive seen ways of bands hiding songs on cd's be it you have to listen to the whole thing in order to access that last hidden track, or you have to skip ahead or what have you, but what if you had to seek backwards? what if there was a song 0 on a certain cd or album? "the reason they arnt aware of it is because they'd never think to play it" got me thinking along those lines, but who knows