I ran into an interesting one today. A failed microphone battery that at first glance was obviously a leaking Duracell AAA cell.
But on closer inspection after getting it out of the unit was a clever clone using exactly the same paint job copper top, black body and white writing but instead of Duracell it said "Golston". The battery had leaked quite badly and caustic had damaged the unit.
Seems Golston are a real Chinese battery company and these fakes no longer form a part of their product line according to their website. Any seen them for sale in the UK?
They seem to work OK as alkaline batteries as long as you don't leave them to leak all over after they have fully discharged. The result with pink caustic goo everywhere was not nice to handle.