Maybe you like that Mackeeper banner or to pay ransom for getting your files decrypted...
In 2012, there was the Flashback Trojan that infected 600,000 Macs. In 2013, a targeted attack hit OS X developers at Microsoft, Facebook, Twitter and Apple itself. In 2015, the XcodeGhost attack poisoned hundreds of OS X and iOS apps. And in early 2016, the first known piece of encrypting ransomware for Macs appeared.