Eeeenteresting. I like it. A bit mad off one of those spells to exile a chunk of your library like Demonic Consultation, but there aren't many of those.

I think at the moment the "normal" additional cost will need paying when this comes off suspend, which makes the suspend fairly pointless. There's probably a way to phrase that to have it work; perhaps just "As an additional cost to cast ~, if you cast it from your hand, ..."

I added that. Too bad it can't be "As an additional cost to cast Gale Dancer from your hand..."

Hmm... you know, maybe it can, actually. I think that'd work.