I like that this card doesn't do that well in mono-fire. Great synergy with though, as you said. Gravity too. I still don't get why the immaterial part is there if the creature is going to die that turn.
Immaterial prevents maintaining any possible health heavy creatures, such as Basalt Dragon or Flying Titans, from staying on.
The immatirialness is to prevent using this spell more than once on the same creature. If it was not for the immatirialness, new OTK I think (with titan)
you could sitll build a deck aorund this, fly a titan, buff it up with pet, wait 6 turns, throw this out...it could work.
Well, I was seeing this more as an additional CC of sorts.