The Minotaur is a horrendous monster with the huge head of a bull. It attacks Percy and Mom when Mom attempts to drive Percy and Grover to Camp Half-Blood. Percy realizes that the Minotaur doesn’t see well; it navigates by smell. Knowing this, however, isn’t enough for Percy to emerge entirely victorious from his battle with the monster. At first, Percy believes that the Minotaur killed Mom—but in reality, Hades takes her to the Underworld. The Minotaur’s violence also severely injures Grover. Percy manages to rip off one of the Minotaur’s horns and then kill it. Later, at Camp Half-Blood, Percy learns that it’s impossible to slay monsters for good—he slayed the same Minotaur that the Ancient Greek hero Theseus did.