On the album Fireball by Deep Purple, there's a song called "The Mule", which opens with the following lines:
No one sees the things you do
Because I stand in front of you
But you drive me all the time
You put the evil in my mind
In Asimov's Foundation series, there's a character called The Mule, who manipulates others using his psychic powers, remaining out of sight himself.
Is the song based on this character, or are the similarities just coincidence?