Is there a way to create a black lightning?

In the texture of the lightning effects, black = alpha, right?

Or am I missing something.

Nope, alpha is done on a separate channel or by erasing the texture. As long as the Lightning model has its blending mode set to AddAlpha in the material, black lightning is theoretically possible.

But not by texturing alone.

So basically I'd have to make a lightning model, and tinker with the alpha there?

Oh bugger.