In the spring of 1986, in the bedroom of a walk-up apartment on South Beverly Drive in L.A., a semi-struggling songwriter named Mark Mueller pressed “record” on his rudimentary reel-to-reel tape recorder, sat down at his Roland Juno 1 synthesizer, and started thinking about ducks.

Disney was looking for a theme song for a new animated series called DuckTales. They wanted a sense of adventure and excitement, a tune that would complement the technicolor energy of the show itself. Most importantly, Disney’s music executives explained, they were after a poppy, radio song—not a “cartoon song.”

Mueller’s agent recommended that he shouldn’t get his hopes up.

A few decent artists had recorded his songs over the years: George Benson, The Captain & Tennille, Syreeta Wright, Lou Rawls. He’d written the first single off opera singer Plácido Domingo’s first, and only, pop album, and the Pointer Sisters had recorded a song of his for the We Are the World charity record.

Even so, the 30-year-old’s songwriting career had mainly consisted of a series of near-misses. He had stacks of cassettes of demos for songs no one wanted. Luckily, he had just scored his first hit: Heart’s “Nothin’ at All.” It was on the strength, and airplay, of that track, that he was able to obtain a meeting with Disney.

And, before long, duck inspiration did strike. That day on South Beverly Drive, the chords, the melody, the lyrics—verse, pre-chorus, chorus, bridge—came pouring out of him.

Read the full story at Vanity Fair.