sentences:  Additionally, "Dark Harvest" was originally supposed to be called "The Hearts and Lungs of Zim's Darkness", but Nickelodeon denied this title.In response to these censorships and restrictions, the writers of "Invader Zim" slipped in ways to poke fun at Nickelodeon, or to simply go against their wishes.This includes the character Nick, who is a boy that is always happy and a not-so-subtle reference to Nickelodeon's frequent demands that Vasquez make the show "happier" and more appealing to certain viewers, which Vasquez always detested.