eidolon vs prodigal son

eidolon

noun
  • A phantom, a ghost or elusive entity. 

  • An image or representation of an idea; a representation of an ideal form; an apparition of some actual or imaginary entity, or of some aspect of reality. 

  • An unsubstantial image, spectre, phantom. 

prodigal son

noun
  • Someone who returns home from travelling or exile or who is welcomed back after disgrace, especially having repented of former extravagant or immoral behaviour. 

  • A marine fish, the cobia (Rachycentron canadum). 

How often have the words eidolon and prodigal son occurred in a corpus of books? (source: Google Ngram Viewer )