A ransomware called "Petya" is spreading fast, just like the "WannaCrypt" ransomware, more info on that here. Ransomware is a type of computer virus that limits what you can do with your computer until you pay money, in this case, this one encrypts your files until you pay for a decryption key. Encrypting data scrambles it so that it cannot be read without the decryption key. This ransomware, just like WannaCrypt, uses a security flaw patched in March by Microsoft in Windows to spread.
An image of the ransomware:
Staying Safe
We recommend that you read this information now to prevent your devices from being infected.
More information
This video by danooct1 demonstrates the ransomware in action: