As the mutts attacked at the Cornucopia in "The Hunger Games" by Suzanne Collins, Katniss realized that they were not ordinary animals but were genetically engineered creatures that resembled the dead tributes. These mutts were created by the Capitol using the DNA of the dead tributes, which made them stronger and more deadly than natural animals. This realization added to the horror and brutality of the Hunger Games, and forced Katniss and the other remaining tributes to confront the cruel and twisted nature of the Capitol's power.