The next sentence: Hay un error en la factura.
You are handed the bill, and there is egg on it – “Ei” in German (hay); the clerk has obviously just had breakfast and spilled some. That is a little awkward – “unangenehm” (un). He lays a pipe – a “Rohr” – on the bill so it does not blow away (error).
Suddenly a duck (“Ente”) waddles across the counter, laughing – “lacht” (en la). He does not hesitate for a second (“fackelt nicht lange”), throws a cloth – a “Tuch” – over the duck and quickly carries it off (factura).