A Random

SCIFI.radio story

Earth encounters a group of time-traveling tourists on a sightseeing trip to the past who want to plug us into a power grid and use us as living batteries even though they are only slightly radioactive who tend to stutter under pressure when confronted by the army, navy, air force, space force and/or marines , but scientists create a new weapon which turns them into weird rocks.
The End.and then they kill us all.
The End.