You create a spear made of crackling energy. This magic weapon lasts until the spell ends. It counts as a simple melee weapon with which you are proficient. It deals 2d8 force damage on a hit, has the reach and uses you spellcasting ability modifier. 

If you have the Agonizing Blast eldritch invocation, you gain the ability to add you charisma modifier to the damage of attacks made with this magic weapon. If you have the Eldritch Spear eldritch invocation, you reach of this magic weapon increases from 10 feet to 15.

At Higher Levels. The damage dealt on a hit increases by 1d8 for every level above first you cast this spell at.