What stories does Viswamitra tell Rama while in the forest during his initiation?

Viswamitra tells the story of Vamana, an avatara of Vishnu who took on the form of a dwarf in order to stop the machinations of King Mahabali, who sought to rule earth, heaven, and the underworld. Viswamitra's asrama is in the holy place where Vamana vanquished Mahabali, but this place has been infested by demons, and the young princes need to defeat them.