The Mist (2007)

David Drayton and his eight-year-old son Billy are among a large group of terrified townspeople trapped in a local grocery store by a strange, otherworldly mist. All the shoppers have no clue what is going on until an old man runs in the market with a bloody nose and declares 'Something in the mist!' - creatures with large squid-like tentacles that have mouths, teeth, and arms. As reason crumbles in the face of fear and panic, David begins to wonder what terrifies him more: the monsters in the mist or the ones inside the store, the human kind, the people that until now had been his friends and neighbors?