Now this is quite interesting. A new piece of malware called "Popcorn Time" encourages its victims to infect others. The ransomware, which is not related to the same-name video streaming media player, is unique because it offers victims two options to get their files back. The first option involves paying a certain amount of Bitcoins to an anonymous account, while the second option involves infecting two of your friends (or enemies) with the ransomware.
As BleepingComputer reports, this is a "feature" not seen in any other ransomware:
In a move that we have not seen with any other ransomware, the ransomware developer offers a "nasty way" for a victim to get a free decryption key by having them help to spread the ransomware. If two people become infected via the victim's "referral" link" and pay the ransom, then the victim will supposedly get a free key.
To facilitate this, the Popcorn Time ransom note will contain a URL that points to a file located on the ransomware's TOR server. At this time the server is down, so it is unsure how this file will appear or be disguised in order to trick people to install it.