Energy Blade

You cause magical energies to coalesce around a melee weapon that you are currently wielding, extending the range of your melee attacks by 5 feet and causing 1d8 additional force damage on hit. Any attack made against a target within the extended range is made using your spell casting modifier for attack and damage rolls.

Casting this spell at 3rd level or higher increases the force damage by an additional 1d8 per level above 2nd, but the surge of energy makes it impossible to concentrate on the spell causing it's effect to end immediately. 

If the spell is being concentrated on, you may use a bonus action and recast the spell at a higher level causing a surge.