This enau fruit (boh jok) is made into food, the name kolang kaling. If in Aceh, people make kolang kaling on fasting boast.

Kolang kaling, surce
There is a story about this fruit
Around my village, a dozen years ago. There are bulek (an overseas -foreign-, from Europe or America, and so on). They are the people at the gas company, who are around it.
They used to run every Sunday, around the hills, bushes.
At one point, they accidentally got nettle leaves (daun jelatang), touched. Their body itches itch.
Finally, when they arrived at the village, they found a group of people boiling fruit.
The bulek, complaining about his distress. So, there is a person who joked, he asked the bulek to smear the body parts affected by nettle leaves, with the sap of the fruit of enau (aren).

Nettle leaves, source
Without thinking long, without question again, the bulek directly follow the instructions (jokes) it.
So the person who gave the suggestion was surprised. He slowly leaves the place, for fear. She thought, why such stupid fools.
Strangely, the itching in the body of the bulek disappeared, after being smeared with the sap of the enau fruit. Then, he looked for the person who gave the advice earlier, to be thankful. Of course, that person could not be found, he had run away in fear, feeling guilty, why he was joking. Finally, the bulek did not find the person who had given that advice.