That’s a really interesting anecdote. I never heard of it.
Should be a James Wan film (the Conjuring, the Nun, Saw, Lights Out...). He’s from Malaysia, not Indonesia but that doesn’t matter.
It’s a very strange tradition. It was probably rather safe to perform those rituals when this tribe was for the most part isolated from surrounding islands and tribes.
They were sort of incubated from diseases that never happened in such close quarters. Then, the travelers arrived, followed by businessmen and military from other lands. ‘Eden’ was now debauched, like the rest of the known world.