User blog comment:FairyRaven/Fairy Tail Chapter 306: Gray VS Rufus, Review and Commentary/@comment-2106167-20121102091219

I think what Rufus memorized were "basic" Ice-Make (spiky masses of ice, as shown in Freezing Sword of Black Lightning) and Ice-Make: Shield, as shown from him pronouncing such spell's name before nullifying him. To me, it looked like Rufus melt the ice from Gray's Unlimited technique while at the same time attacking him. And as for the finishing blow... Again, that might have been due to Gray's Ice Bringer swords being different in shape from his standard Magic, from him approaching Rufus too fast and using his own flames as a "smokescreen"... or from Mashima being unable to explain that :P