Because the trademark "King3GPCom" is not actively maintained, malicious actors host fake installers that look identical but contain ransomware droppers. A legitimate installer is ~15–22MB. If it is 850KB, delete it immediately.
Navigate to or Privacy (this varies by phone manufacturer). king3gpcom install
If your default player cannot open a 3GP file, you can use a universal player like VLC for Android or MX Player. king3gpcom install