'Billy's Balloon' is sort of brilliant. It is also quite sadistic, but the more sadistic it gets the more you will probably laugh. Just do not take it too seriously. It shows how a balloon is hurting a child, Billy I guess, by lifting him up and dropping him to the floor. You might think this joke will grow old in about a minute, but this animated short, around five minutes long, invents new little things to keep us laughing.
The simple looking animation is perfect. It makes the sadistic events a little colder but at the same time it helps you realize easier that it is just an animated short. Animator Don Hertzfeldt has done a terrific job here. For something a little more disturbing, but equally good, I can recommend his 'Rejected'.