gladius vs penfish

gladius

noun
  • A pen, a hard internal bodypart of certain cephalopods, made of chitin-like material. 

  • A Roman sword roughly two feet long. 

penfish

noun
  • A squid. 

  • Any of various porgies of the genus Calamus 

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