One for the Magpies

Always fear the magpies.
One for suffering for all eternity.
Two for a happy, but fatal addiction.
Three for a plague.
Four for a parasite.
Five for eternal inferiority.
Six for a victory stolen.
Seven for a secret,
You were never meant to know.
Eight for Heaven.
Nine for Hell.
And ten for the ire of a supernal clown.