Bombinomicon is a $6.66 (discount) 15th edition book of forbidden knowledge and ancient wickedness, and the smarmy Host of Hell. Bombinomicon has been in the possession of Merasmus the Magician, who was known to summon it to cast the horror of reading upon mere mortals. While despising the magician, Bombinomicon enjoyed showering veritable fountains of bombs on the mercenaries at the wizard's command. This arrangement did not stop the Bombinomicon (when Merasmus wasn't watching) from turning the mercenaries' heads into bombs and sending them after Merasmus.
Bombinomicon tricked the boy Tavish (young Demoman) into gazing upon the tome's pages. This enabled Bombinomicon to totally haunt the boy's left eye. Quick action by the wizard saved the boy's life, casting away the haunted eye. The haunted disembodied eye became MONOCULUS.