The Slipknot song that begins with the sound of a siren is called "The Pulse Of The Maggots". It is the ninth song from Slipknot's third album, Vol. 3: released in 2004.
The song is about how Slipknot will always be there for their fans even though they did break up for a little while. Slipknot fans are affectionately called "Maggots."
The title was inspired by the constant movement of fans at Slipknot concerts. Check out the lyrics at Songfacts.com.
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