Every file on your computer has a file extension—a suffix consisting of a period followed by a few letters (like .jpg , .pdf , or .mp4 ). This extension tells your operating system which program should be used to open the file.

The actual file extension is always the very last one listed. In the case of JULIE.mp4.mkv.mp4 , the file is technically attempting to execute as an MP4, but file names stacked with multiple video containers are a massive red flag for digital manipulation or corrupted data containers. ⚠️ How the "Double Extension" Trick Works

Believing it is a movie, the user double-clicks the file. Instead of playing a video, the computer executes the .exe program, potentially installing ransomware, spyware, or trojans. 🔍 Red Flags in the File "JULIE.mp4.mkv.mp4"

By default, operating systems like Microsoft Windows often hide known file extensions to keep the interface looking clean. Malicious actors exploit this default setting to engineer visual traps: