Certain fan-made projects, such as Sonic Gather Battle , have been reported to include malicious DRM that functions as spyware or malware if it detects tampering. How to Open RAR Files on Windows, Mac, and Mobile - Avast
Files like "hedgehog.rar" or similar Sonic-themed downloads have been identified as ransomware that encrypts your personal data and demands payment (e.g., $400) to recover them. Download hedgehog rar
Some downloads may contain a "Hog Error" virus, which manifests as a dancing hedgehog on your desktop, prevents you from clicking anything, and can cause permanent system damage. Certain fan-made projects, such as Sonic Gather Battle