Rain -> Grass -> Cows -> Milk -> Butter

  

Sources:

https://en.wikipedia.org/wiki/Norwegian_butter_crisis

https://nowiknow.com/the-great-norwegian-butter-crisis-of-2011/

https://slate.com/business/2011/12/norwegian-butter-battle-an-absurd-dairy-shortage-and-its-very-valuable-economic-lessons.html

Music: https://www.purple-planet.com