The discussion continues, and Vanni Fucci continues to display such obscene behavior and utter such awful blasphemes that the snakes gather together—ignoring the other sinners—to try and stop him. For once, Dante finds the punishment he encounters satisfactory, glad that Fucci suffers because he has never encountered another soul who is so blatantly rebellious against God during his journey. Eventually, the snakes prove useless, so an enraged centaur chases after Fucci, prompting him to depart. Free from Fucci’s distracting monologue, Dante observes a dragon with wings spread and a fiery breath on the back of the centaur, who Virgil identifies as Cacus.

Unexpectedly, three spirits appear and inquire after the travelers’ identities; Virgil pauses to respond to the query, but Dante senses danger and subtly signals to Virgil that he should be careful with his words and not reveal too much.

Once again, his instincts prove useful: out of nowhere, a six-legged worm appears and attacks one of the spirits, latching onto it with its claws. The two beings merge together, resulting in a monstrous beast with two heads and one body. 

Suddenly, a lizard appears and jumps onto another spirit, biting its mouth. Smoke pours out of the spirit's mouth and mixes with the smoke from the lizard. The lizard transforms into a man, while the man turns into a savage beast, expressing a desire to exact this same suffering on all others. Only one spirit remains unaffected by these bizarre transformations, and he appears just as confused by the events as Dante. The strange events vaguely remind Dante of stories he has read in the past, but nothing compares to what he is seeing in front of him, and he remains terrified.