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 are radioactive and cannot be destroyed by a bunch of Elvis impersonators but one cunning young man somehow convinces them that people are okay and they are turned into weird rocks that all look suspiciously like either Elvis or Madonna, but nobody can agree on which one it is.
The End.