The next sentence: Quédese la vuelta.
You give the taxi driver a little more money than he is owed. He turns the note over (kehren in German), stretches it (dehnen) and pulls a lake (See) over it (quédese). When you tell him he can keep the rest, he laughs (la).
Then he says you have a wish, and gives you a cup with elk antlers on it (vuelta).