Possible Clues:

• That's a nothing at all to make you die, by the sound of it
• It takes a nothing to make one die, by the sound of it
• Dye source
• A river almost blue
• Indigo gets a zero
• Seems a nothing will make it die, by the sound of it
• AO till all is blue?
• It seems a nothing could make it die, by the sound of it
• Blue as a result of getting a duck?
• The sort of a nothing that make one die, by the sound of it