"You recall that the god was supposed to visit from time to time -- to play with men ...to instruct."―Francisca Uribe Del Arco[src]
Viracocha was a god in the Incan belief system. When he interacted with humans, he frequently took the form of an old man.
In 1937, after Indiana Jones had escaped from being a sacrifice on a snow-covered mountaintop by Ricardo, on Felipe Uribe's orders, a half-frozen Jones saw a ghostly old man who pointed him to a baby llama. Jones huddled next to the llama for warmth and survived the night.
The next day, while walking with the llama, Jones encountered another old man who spoke to him and guided him to a village on Taquili, in Lake Titicaca. After a night in the village, Jones hired the man to guide him and some other villagers to the spot marked on the Vasco de la Posco's map leading to the Arms of Gold. After entering the tomb, the man mysteriously disappeared, leaving Jones to discover Pachacuti's remains alone.
When Felipe arrived with his neo-Incan followers and fought Major Claude Reed-Whitby and his men, one of the neo-Incans called out the name of Viracocha upon getting shot. After Felipe's forces won the fight, Felipe began a ceremony to use the Arms of Gold and chanted to the Incan gods, including Viracocha.
A week after Jones and Francisca Uribe Del Arco survived the collapse of Pachacuti's tomb, an old man brought Indiana Jones the bill at a restaurant in Lima. When Jones realized that he had seen this man before, Francisca explained that it may be the god Viracocha guiding and playing with him.