This is an .mp4 video file, a common format for sharing videos via text, instant messenger, or social media apps.
Scammers often send unsolicited files ( .mp4 , .zip , .pdf ) or links in a tactic called smishing (SMS phishing) to bypass spam filters. received_8499270873447805.mp4
If it's from an unknown sender, I highly recommend deleting it immediately as a precaution against scams. This is an