Helter Skelter

The Beatles song and Manson's insane murderous "vision" both pop into my head when I hear helter skelter.

I thought it was just a slang term for craziness or madness.

Wrong.

From Wikipedia...

A helter skelter is a funfair or amusement park ride with a slide built in a spiral around a high tower. Users climb up inside the tower and slide down the outside, usually on a mat. The term is primarily (but not exclusively) found in British English. The ride inspired the Beatles song of the same name.

The Beatles studio recording of Helter Skelter...