i just looked up Blast Burn on Bulbapedia. that led me to an article about the Gen 5move "V-Create" which is the signature movie of Victini and has a base power of 180. and check this shit out:

"If a Fire-type Pokémon has the Ability Adaptability (which is not possible without Skill Swap or Entrainment), is holding a Fire Gem, and uses V-create against a Pokémon with the Dry Skin Ability that has a double weakness to Fire (such as Paras) while it is sunny, the move will reach an effective power of 4050." - Bulbapedia