It crashed into the Alps with a high rate of velocity and therefore buried itself into the glacier. The invader from space looking for a world to conquer was immobilized in ice.
It took years for it finally to come out. The protoplasm of an alien in a shape which could not be described except it was a mass of a shape. No eyes, no nose and no face. But inside the blob was an intelligence.
It crawled out onto the ice. It was dying from the exposure to the cold. And then it seized a moment of chance for a yeti came upon it. It feasted on the yeti and became one. A yeti which could survive the cold. It was safe.
The Sherpas came upon the yeti and in a fit of rage and fear killed it with their spears. The alien thus died. An alien which had come to conquer earth died in a yeti which was a peace loving creature.