Planet Popstar simply has enough. Dream Land's residents get mad every time Planet Popstar gets destroyed. So, they get their revenge. In Kirby 64, Rock Star appears to have been destroyed. This is my theory on what happened to it. The inhabitants expected that to happen and well, Rock Star got Uno-Reversed. The reason why I put a blue atmosphere on Rock Star is because in game, Rock Star's sky is blue so it makes sense. Now that's what I call, Karma.
Credit to Nintendo and HAL.