If that would be a post-credit scene and not an opening one, it could be the very ending of a movie Battleship (2012). Article + screenshot

If that would be a post-credit scene and not an opening one, it could be the very ending of a movie Battleship (2012). Article + screenshot

Battleship's post-credits scene unfolds in Scotland, where three teenagers come across a mysterious cubical structure that seems to have fallen from the sky. When an adult joins them and budges the object open, a pair of alien arms spring out of it and sends them fleeing away in fear...