The Zython was offered in the 1977 Mattel Catalog as an alien character to go alongside with Mattel's Space:1999 action figure line. It never appeared in the series but was a rather welcome addition to the line which desperately needed more flair.
However, sales on Space:1999 merch weren't strong enough to warrant a wide release and the Zython seems to have only been offered via this contest for a German comic book above (Thanks Eddy for the scan). It's speculated that less than 300 of these were made, we'll probably never know for sure but a few have trickled out of Deutschland over the years.
But of course, this is Mattel we're talking about here, they'd never let a good toy mold go unused, so Zython would later appear in the amazing Mexican version of Big Jim (known as Kid Acero), which was produced under license by a company called CIPSA, who would dub him Nocton an alien enemy of Kid Acero.
So, while I'll probably never own a Zython (the last one went for just under a grand), I was able to buy a Nocton in the 1990s and still have him to this day. One day I hope to track down his scepter.
