This set is a ridiculously good staller against those who are unprepared. Toxic, Sub, Roost. Sub can be used with Leftovers to stall Stone Edge users out of PP without any practical risk assuming you can take a hit after Roosting, and Toxic + Sub can wear down a lot of Bulky Waters quickly. Most other Pokemon are helpless to defeat Moltres, even if you're Roosting in their face. This set needs SR support to work best, though. The EVs can outspeed neutral base 100s with minimal EV investment, and also allows for some extra firepower. HP Ground is an acceptable alternative for Typhlosion, Blaziken, and their friends (especially Heatran in OU.)