Weird, I thought. Then I noticed that the two prongs on the new one were hollow and seemed to correlate with those on the other piece. Even more odd. I pushed them together and the prongs connected and clicked into place. Then I noticed writing on the top piece. It was a brand name but as far as I know - and, as I've now felt compelled to go through every drawer in the kitchen and trawled the manufacturer's web site, I'm pretty sure - I don't have and, if I remember correctly, never have had anything that made by this particular manufacturer.
We'll probably never know where it/they came from but I have a theory - formed after living here for many years of strange things turning up without explanation. We're either located on top of a portal into another dimension or we have some very tricky fae folk, with far too much time on their hands who like to amuse themselves at our expense, living nearby. The only logical conclusions, don't you think.