Just something I made the other day. Fireball was sculpted in ZBrush, lens dirt was added in Photoshop.
No UV-Unwrapping was involved. The effect was achieved by making a subsurface material with a mix of emissive and fresnel nodes and placing very bright lights inside the fireball itself to illuminate it.
That is definitely a cool effect! You should try some sort of moving displacement to get a cool slow-mo ripple effect.
And don’t forget you can have lens dirt inside Unreal through the Post Process Volume (if you want).
And that displacement idea is absolutely awesome! Totally gonna go try that. Or, better yet - UV map the thing, and add a tileable noise texture to the fresnel effect, and have that tie into displacement!