Black Sabbath song
celebrating the
ganja, opening their 1970 release
Master of Reality. The song actually opens with a 99% feedback
delay loop of someone
coughing up a massive
bonghit.
The main guitar riff (A A D C# C C D, all E-form power chords) is found quoted by many other artists, including the end of the Red Hot Chili Peppers' "Give It Away", and it is "covered" by the Butthole Surfers in their magnum opus, "Sweat Loaf", off Locust Abortion Technician.