In 1989, producer Tom Ruegger had led an exodus of Hanna-Barbera staffers to restart Warner Bros. Animation. At first, the studio was constantly under threat of closure. However, under Fred Seibert's guidance, Hanna-Barbera's new staff (whose ranks included Seth MacFarlane, Butch Hartman, and Genndy Tartakovsky) created a new generation of Hanna-Barbera cartoons in the 1990s such as "2 Stupid Dogs", "Dexter's Laboratory", "Johnny Bravo", "Cow and Chicken", "I Am Weasel" and "The Powerpuff Girls". Alongside these Hanna-Barbera cartoons, shows from other companies also premiered on the channel such as "Space Ghost Coast to Coast", "Ed, Edd n Eddy" and "Courage the Cowardly Dog". These shows were designed to appeal to adults as well as children, and thus incorporated plenty of "adult humor", such as pop-culture references and veiled sexual innuendos.