Kieselguhr!
I only learned this word a couple of weeks ago. A cow-orker said that he didn't actually want anything frozen in carbonite, but he wanted a coffee table made out of a big slab of it. So he said to me, "What is carbonite, anyway?"
What, in the real world? So I told him it was an old explosive. Probably not good for most coffee tables . . . especially if you have a couch that's on fire, mind you. Naturally, he did not believe me, so he looked it up, and said (too loud for work) "What the @#$! is kieselguhr?"
Turns out to be an old (German) name for diatomaceous earth, one of the ingredients used in some recipes carbonite. I'm trying to start using it as a mild exclamation. Partly because it's just easier to say than Unglaublich.