An organ grinder is someone who ‘grinds’ an organ (musical instrument). They are typically accompanied by a monkey, who does tricks, attracts attention, as well as collect tips from passers-by.

One of Winston Churchill’s famous quotes was “Never hold discussions with the monkey when the organ grinder is in the room”. This means talk to the boss rather than waste time with his workers.

Therefore, this dream, combined with dead chimpanzee., could be interpreted as a foreshadowing of Gillis’ future as Norma’s 'pet’.

The fact that the music was still playing when he awoke, and that his belongings have been moved in, shows this dream starting to become a reality.