Teens running, police converging and a grey splotch that appears to be moving: Videos from an outdoor mall in Miami stoked wild claims this week on social media that aliens had landed on Earth. But ...

Aliens are back in vogue. Haven't you heard? Fascination with little green men piloting saucer-shaped UFOs was long the purview of tinfoil-hat wearing conspiracy theorists and "X-Files" devotees. But ...