Malware
PLAY
aka PlayCrypt
According to PCrisk, PLAY is the name of a ransomware-type program.
PLAY, also known as PlayCrypt, is a Windows malware family.
Background
PCrisk identifies PLAY as a ransomware-type program. Such malware works by encrypting a victim's data and then demanding payment in exchange for decryption.
When a sample was run on PCrisk's test machine, it encrypted files and tacked a ".PLAY" extension onto their names, so "1.jpg" became "1.jpg.PLAY", "2.png" became "2.png.PLAY", and so on. After finishing encryption, PLAY dropped a text file called "ReadMe.txt" onto the desktop.
Source: Malpedia (Fraunhofer FKIE).