After playing the witcher for a while i began to think of that spell in the opening cinematic that Geralt uses to stave off the creature, though i have not come across it yet, i believe it must be an upgraded version of the Aard sign since it seems only to repel the creature rather than hurt it, is it possible to obtain this spell through the leveling of the Aard sign or was it just a fancy new spell created for the cinematic?
Alas, like many book-video game crossovers, the character in the books (and, by extension, the cinematics) has all sorts of cool tricks that really just wouldn't all be able to fit into the engine chosen for the game. It is the Aard, but not in any form you can cast in-game.