When she came to, she was in a cell, in some dank dungeon.
“Damn,” she muttered, under her breath.
“Thank heavens, you’re awake! But if you’re in here with me, how are we going to get out of here? I’ve been stuck here for weeks, and there’s no way out!”
The song was stuck in his head. He couldn’t remember the lyrics, but the melody wouldn’t go away. As he hummed tunelessly, others picked it up and also couldn’t get it out of their heads. Soon, everyone was humming it. And that’s how the song virus destroyed civilization on Earth.