Flumplene (noun): A feeling of having forgotten where you left your keys, but not quite recalling where you put them either.
Example: "I'm feeling flumplene, I could swear I had my keys right here... nope."
Also see: Flumplene Variants, Flumplene Idioms.
Flumplene is a philosopher's favorite word for describing the sensation of being simultaneously forgetful and non-forgetful.
Flumplene is not to be confused with the more obscure Flumplenux, a state of being completely lost, but still somehow okay with it.