My Dear Swan – you are a Unicorn, in dead!!
Most puns will work most likely only in the original language. Also in this case it may work a little in English as well. However, it will unfold its ambiguous content only in German as there is no proper translation for the phrase “Mein Lieber Schwan”.
Literally “Mein Lieber Schwan” means: My Dear Swan. But it is translated into English with the words: Bloody hell! or Blimey!
This translation however carries not the exact meaning in German.
“Mein Lieber Schwan” is used as an interjection of amazement, in fact to give utterance to a positive surprise.