The December update of fan game Sonic Gather Battle, has been found guilty of malicious code and is now considered malware. As noted by GerbilSoft on our forums and found by several Discord and Reddit users, Gather Battle will do the following to your system:
If any open window has certain keywords in the header (such as “cheat” or “hack”) it will close that window without your permission, including folders, programs and browsers.
If it thinks you’re trying to tamper the game, it will remotely blacklist your system from running the game, and the only way to unblacklist it is to convince the developer directly.
It exhibits a lot of other malware-like behavior, including storing a hash of your system information on a remote server, modifying system files, and running unusual and shady system commands in the background.
If you downloaded the December update of Gather Battle, the current recommendation is to delete the game immediately and run a scan on your system. You may also want to consider restoring your system if possible. If you’re truly curious, you can check out this YouTube video showing off the game’s intrusive measures at work.