Pain Taught is the best Spell for a Boss, as it takes the spread-fire idea 
and turns it inside-out! Instead of diverging, the shots converge, meaning 
ONE enemy takes it all! Can really SHRED a Boss, or any other tough enemies.
Also inflicts Poison, and Poison damage is based on the health of the enemy.
(As opposed to burning damage, which is based on the Spell, and therefore 
constant)