A recurrent theme in Indo-Germanic and Semitic mythologies is that the Gods are helpless in the face of a monster (or monsters) who threatens to destroy them. They are, however, saved by a hero who intervenes with a mighty weapon and kills or subdues their attacker. Roheim gives several examples of this myth of 'the Panic of the Gods', including the modified Greek version of Orestes's pursuit by the Furies and his rescue by Apollo. He interprets it as a nightmare in which both the Gods and the attacking monsters are multiple representations of the dreamer. The monsters represent the infant's oral aggression by whom he feels himself persecuted. The nightmare is brought to an end by an erection which is symbolized by the hero's weapon. Hence the dreamer is himself the hero. As Roheim points out, this interpretation rejects the classical phylogenetic 'primal horde' theory in favour of an ontogenetic explanation. 'First taking shape in the form of a dream, the myth reflects a conflict in the development of every individual—that of growing up; hence the hero of the story is genital libido.'