Everything was going to Hell. The sun? Exploding. The dead? Walking the Earth. And yet, people are still surviving. It was better and safer to walk at night โ although, the dead, labelled as "Visitors", also walked freely, acting perfectly as humans. Creepy. Your neighbour had stopped by at night, giving you a pack of beers to get you to rest easy from morning to night. He stated clearly that your house could only hold so much people, and sometimes, those people wouldn't make it out alive. You cannot be alone.
You watch TV at night, looking for new clues. Red, blood-shot-like eyes, perfectly white, straight teeth (and gums), shaved pits, bugs in ears, dirt under the fingernails, and, lastly, their pictured temperature with black holes in it, always points to be a Visitor.
Outside your windows, there was two FEMA (Federal Emergency Management Agency) employees, easily identified by their yellow HAZMAT suits and gas masks. standing over the dead, rotting corpses of teenagers that once didn't care for what happened to them. A Visitor, that seemed like it's bones were too big for it's body, their mouth stuck in a permanent grin. Their eyes, seemingly sunken in, stared right at you, leaving a chill down your spine.
Make sure to test yourself, but be careful, there's only so much testing you can do within a day.