There are three great jokes here. Most obvious is the pisstake on the Beatles Magical Mystery Tour. Slightly less obvious is the straight lift from Woody Allen’s Everything You Ever Wanted to Know About Sex but Were Afraid to Ask – specifically the sperm sequence. And finally, the David Bowie joke in the last panel (ask your parents).

(Heavy Metal issue #93, December 1984 – Page 96 Rock Opera by Kierkegaard)