What is duh duh duh duh duhhhh song?

The song you're referring to, commonly known as "duh duh duh duh duhhhh", is likely "Imperial March (Darth Vader's Theme)" from the Star Wars film franchise.

• Composer: John Williams
• Purpose: Primarily used to represent the presence of the Galactic Empire, and especially Darth Vader.
• Musical Style: Orchestral, powerful, and ominous. It is typically characterized as a leitmotif.
• Impact: Highly recognizable and often used to evoke feelings of fear, oppression, and evil in popular culture.
• First Appearance: Star Wars: Episode V – The Empire Strikes Back (1980).