It's supposed to work the same way as arcing bolt does with forked lightning, right? That is, it should add a short duration immoation to any unsaved hit. As it is though, it doesn't seem to do anything at all. I've used it around 200 times, on low and high level monsters, in raids and in pk, and it's never immolated anything. This is really minor, and only affects a small number of the members of one class, but still, I like flashy edges like this!