In a story over at Motherboard they cover the development of so-called Ransomware for the Mac. The original story covers a newly minted prototype, but there was also an update that detailed an earlier prototype that was released a few weeks ago.
I’m not trying to raise any alarm bells, there is zero evidence that any of these are in the wild. Pair this with the news about adware wrappers on Mac Update and you should just know to be careful where you go online. Definitely don’t download any files or programs from places you don’t know.