Parents need to have fun every once in a while.
The older one gets, the more they realize that age is just a number. It isn't really indicative of a person's maturity level. In fact, all it does is grant more responsibility, which can be used for good or for bad. Having children is one such responsibility, and the ability to own a Tesla Model S is another. However, a child at heart is able to use both of these responsibilities to play some fun pranks with the Tesla's self-driving features like summon and auto park.
This particular child hilariously gets shaken up by the prank that his father of the year plays on him. Given the summon feature's recent mishaps, he may have a reason to be afraid.