Booming Blow is a special that can be used by Fighters with Special/Fighter Level 7. When used, your next attack will do a lot more damage and will make an explosion sound. If you get a Booming Blow critical hit, it deals a very high amount of damage. Booming Blow doesn't require a target to activate, and uses quite a large portion of your stamina. The stamina cost may not be worth it unless you score a critical hit, so sometimes it is better to save the stamina for other specials.