People were standing in front of the grocery store, queuing for melanin. The shop assistant would mix melanin thickly with water, serve, and people would drink it. However, melanin was in shortage. As melanin sales continued, it would become more diluted. Those people who came earlier and drank thicker mixture would get darker skin tone. Those who came late would buy diluted melanin, and their skin would be lighter.
Some of those late comers got really upset and invented racism. They also declared their lighter skin tone divine.