Eldritch Bolt

After studying intensely at Eldritch blast and it's various enhancements through the forms of eldritch invocations, you successfully managed to condense the cantrip through the use of some of your magic into a powerful bolt. 

The bolt fires off in a 5x120ft line, all caught in it must make a Dex saving throw or take 14d10 damage, half as much on a successful save. 

When firing it off the caster must make a dex save (vs caster's save DC) as well or be knocked back 5d20 ft.