Berlioz's program notes follow. Trick or Treat.
"Songe d'une nuit de sabbat" (Dreams of a Witches' Sabbath)
He sees himself at a witches' sabbath, in the midst of a hideous gathering of shades, sorcerers and monsters of every kind who have come together for his funeral. Strange sounds, groans, outbursts of laughter; distant shouts which seem to be answered by more shouts. The beloved melody appears once more, but has now lost its noble and shy character; it is now no more than a vulgar dance tune, trivial and grotesque: it is she who is coming to the sabbath ... Roar of delight at her arrival ... She joins the diabolical orgy ... The funeral knell tolls, burlesque parody of the Dies Irae, the dance of the witches. The dance of the witches combined with the Dies irae.