A Random

SCIFI.radio story

Earth encounters a group of time-traveling tourists on a sightseeing trip to the past who do not understand us even though they have seen every episode of Firefly who tend to stutter under pressure when confronted by a crowd of people with pitchforks and torches , but scientists create a new weapon which turns them into weird rocks.
The End.but they die from catching the common cold.
The End.