Supernova

Most stars die quietly using up all their fuel through nuclear fusion and fade away into dull celesial objects called white dwarves. But if it's big and hot enough, a star can explode, generating enough heat to create even heavier elements such as mercury, gold, silver. The potassium in your banana may not have had its beginnings on an island in the Caribbean but may have been created a long time ago in a supernova.