I assume this is a La Cucaracha outtake, if not later. For a long time, I had doubts on if it was real, however the quality and spectrogram proving it was tape sourced has led me to believe it is in fact Ween, or at least Aaron tributing Ween in some way. This is a cleaner source than I posted a long time ago, with correct EQ, azimuth and clean ending.
