The skater apologizes. Seconds later the boy's mother appears, furious.
'You ran into my son on his birthday?' she demands and shoves him.
The woman gets hit in the face and then clocks the skater in the face with a right hook. The video ends before the conclusion of the altercation.
Online commentators are split on whether the skater deserved it. Other skaters suggested that the mother should be arrested for assault.
One of the top comments on the video posted on YouTube says: 'With skaters around, that mother should have been watching her kid.... with this video evidence she could be charged with battery and given a "worst mother of the year" award.'
Other commenters identified the park at Cannery Park in Hayward, California, which mixes a skate park, and basketball court into the same space - all across from an elementary school.
They claimed that the skater had a responsibility to be on the lookout for children who could run across his path.