quick metamagic question

[kemmotar]

There was a metamagic feat that made an area spell blow back anyone that failed a reflex save making those that failed the reflex save take 1d6 pts of dmg for every 10 ft they were blown back?

Firts, what's the name of the feat and where can i find it?
Second, whats the best spell to use with it?would a lightning bolt work with it if you hit him straight on so that he was blown back along the line of effect, that being a 120 ft line. Thus if you blast right in his face he takes an additional 12d6 damage?Would that work?

Plus, you could easily throw them off a cliff...try getting out of that...