I created explosion and spark for this shot.
For the explosion, I emitted some particles then copied by metaball,
and render them as volume with My Metaball Volumetric shader.
For the Metaball Volume Shader, Using the particle's age to control emission of smoke to make it like fireball.
Render By Mantra Composition By Nuke
The CG environment is made by my friend, Xiao yang.