From Fireball (1971) by Deep Purple

The Mule (Blackmore/Gillan/Glover/Lord/Paice) - 5:21

No one sees the things you do
Because I stand in front of you
But you drive me all the time
Put the evil in my mind
Used to sing and say my prayers
Live my life without a care
Now I have become a fool
Because I listened to the mule
How can I change when my mind is a friend
Of a Lucifer hid in the ground
Just another slave for the mule