The razor-thin difference between a good practical joke and a cruel one is on display for all to see (and gasp at).

YouTuber Roman Atwood was playing with his son in his Spider-Man costume when he swapped in a dummy dressed as the superhero and "accidentally" threw him over the railing, much to the horror of the boy's mother.

The prank went off as planned, but, man, oh man, is this mean-spirited. This dad's gonna have to sleep on the couch for at least a month.

More From GuySpeed