When the Engineers visited a planet, the Engineer was chosen by the elders of his race to serve as a sacrifice in order to seed the planet with life. The Engineer stood over a waterfall and after seeing a ship, the Engineer removed his cloak and ingested an unknown substance that was given to him by the elders. His entire body structure began to dissolve and he fell into the waterfall, seeding the planet with his DNA, and hastening evolution upon that world.