"Watermelon Man" (Herbie Hancock)

Nothing really prepares you for the first time you hear "Watermelon Man" off Herbie Hancock's 1973 album Head Hunters.  That's particularly true if you're already familiar with Hancock's 1962 original from the album Takin' Off, which is basically a blues set to a swinging, hard bop beat—his attempt to capture the sounds and rhythms of his youth, hearing watermelon vendors maneuvering their carts through the cobblestone alleyways of his native Chicago.
But the Head Hunters track has a different vibe altogether.  It trades a bit of the playful nostalgia of the original for 1970s urban grit, recasting the tune as a laid back slice of electronic funk.  Along with the radically reimagined arrangement, the 1973 track features this otherworldly whistling/howling called hindewhu, a mouth percussion technique that comes from the Ba-Benzélé pygmies of Central Africa.  (It's that sound you hear at the beginning of the track.)
As I learned in a jazz music appreciation class in college (and had to research again because that was a few years ago), Hancock and his percussionist Bill Summers had first heard hindewhu on a field recording of the Ba-Benzélé and were floored by it.  Although the pygmies produce the sound by blowing into whistles made of hollowed-out papaya branches, Summers figured out a way to imitate it by blowing/vocalizing across the mouth of an empty beer bottle, directly into a microphone.