Elementacular - Autodesk Maya Plugin for modelling and rendering of clouds.
This tutorial demonstrates how to use Elementacular to create a fireball effect using emission of light from the cloud volume.
Elementacular allows the artist to directly control the shape of the cloud through manipulation of meshes. The plugin provides real time high-quality rendering directly in the viewport and supports advanced multi-scattering of light inside the cloud for added realism.
http://elementacular.com