LOL Thanks for the lesson. How about the use of the word RATS.
The word doppleganger was first heard used in the movie Journey to the Far Side of the Sun. Interesting movie and the word just stuck. Perhaps because of its German origin and one of the few words I could speak in German :-)
I've know the word "doppelganger" for a very long time and I've not only never seen that movie, I've never heard of it. I first came across that word in some book, when I was a kiddo. It's rather late, I'm getting a migraine, and I have no idea what book it was; sorry.
LOL...I see I need to also teach you German words! :-)