Video: Parents scare kid with life-sized robot dinosaur

I just don't understand these videos. And I've never really understood practical jokes. They're not funny to the person they're done to - they're usually quite mean. And that one finds "mean" funny doesn't strike me as particularly nice. In this video, the parents decide to convince their two year old that something is going to kill him. He knows quite well what a dinosaur is, and that they eat people. So how is this just a cute joke and not, quite literally, parents putting a kid, psychologically at least, into a near death experience?

And before anyone poo-poos my analysis - explain to me how this kid wasn't just convinced that he was about to die. Then explain to me how that doesn't risk scarring the kid? I'm just increasing finding a lot of these videos kind of sick.  Just me?