In Alfred Hitchcock's 'Spellbound,' the quote 'The mind is a strange thing' refers to the film's psychological mystery. To represent the mental instability of the protagonist, composer Miklós Rózsa used the Theremin. This was the first time the electronic instrument was used to represent psychological 'unraveling' in a Hollywood movie. Its wavering, high-pitched tone matched the surreal dream sequences designed by Salvador Dalí. The Theremin’s 'invisible' playing method was a perfect metaphor for the unseen workings of the subconscious mind. This choice became a cinematic legend, proving that a futuristic instrument can define the internal world of a character and the mystery of their most cryptic dialogue.