Rock Slide is basically used to target Mega Charizard X, and it OHKOes anyway. For Pokemon that use it as a neutral STAB move such as Tyranitar, the more powerful option is preferred.Just a question to everyone who's approved this: Why is Rock Slide preferred over Stone Edge. Stone Edge is preferred, in singles, on basically every Pokemon that learns both, so I was just wondering if Stone Edge isn't slashed anywhere, while Rock Slide is, for a specific reason regarding Hippowdon.