Well the Yanomamo's understood how important these film cans were to Alan Yates' crew They thought these silver boxes contained their power.

10 seconds sound clip from the Cannibal Holocaust movie soundboard.

You can hear this line at 00:42:25 in the Blu-ray version of the movie.

Quote context

[...]

- This convinced them that I was the only one capable of breaking the evil spell that had been cast over the Tribe by the murder of the whites...

- Of course, they had no inkling of what was really in those cans.

- How could you explain what a movie is?

- They just felt they were a threat.

- Why do you say threat?

- Well the Yanomamo's understood how important these film cans were to Alan Yates' crew They thought these silver boxes contained their power.

- The power which, I must say again, caused much damage and violence.

- A fantastic story. Thank you, Professor Monroe.

- You're very welcome.

- As we conclude this special interview, we would like to remind you Wednesday at 9pm, here on Pantheon, we'll be presenting part 1 of The Green Inferno.

- The dramatic film testimony, of an extraordinary adventure that took its protagonists all the way back to the stone age.

[...]