Strange family story

I was told a story from my mother that was quite strange so I decided this was the place to get some feedback on it.

The story was witnessed by my grandfather and granduncle(?)and then passed down to my mother. My grandfather lived on a farm in Brazil with many siblings and one day while they were all down by the lake playing a strange boy approached them and began to play with them. They noticed nothing strange at first about him except that his skin was almost pitch black. Then he showed them this strange "power" he had. The boy said,"Watch" and proceeded to stare at a group of birds in a tree near them. Suddenly, one by one the birds fell to the ground dead. After my grandfather and his siblings witnessed this they told their mother and she told the kid to never come back,(apparently she thought he was an evil child). In the end the boy never came back but my grandfather always remebered the story.

I thought this was quite interesting and was wondering if anyone had heard of similar incidents such as this or even had an explanation.

A very strange story indeed.

I have always thought that spirits can not harm living things though.