Focus on Boy Bitten by a Lizard and explain the Symbolism.
According to Leonard J. Slatkes, the painting's symbolism likely derives from the Apollo Sauroktonos theme in which a poisonous salamander triumphs over the god, while the arrangement of various fruits suggests The Four Temperaments, with the salamander being the symbol of fire in Caravaggio's time. The salamander also had phallic connotations, and the painting might have been inspired by a Martial epigram: "Ad te reptanti, puer insidiose, lacertae Parce: cupit digitis illa perire tuis. (Spare this lizard crawling towards you, treacherous boy/It wants to die between your fingers)
Apollo Sauroktonos Martial Caravaggio