Help identifying a piece being sold as "rare prototype"

> Welcome to The Bloks Forum, by the way!



Thank you, your catalog of parts was great to look through, hope you get to add more parts!



As for this part in question, I realise the angle was bad in the first image, let me get a better picture. The "bottom" you see is identical on both sides, like so:



It's essentially mirrored top-to-bottom. This part has never been produced by Lego and I can't find any competitor that have produced it. It is an interesting piece, but I can't wrap my head around as to how it was supposed to be used in sets? I've seen the Mega 2x2 "male:male" plate, but this is a very special case indeed... and there are so many of it, I feel like the brand it came from would've used this in many sets? Either way, if anyone can figure out exactly what we are looking at and which sets it came in, that'd be lovely!