Eldritch blade

This spell creates a spectral blade of energy that follows behind your weapon.    As part of the action used to cast this spell, you must make one melee attack with a weapon against a creature within this spells range, otherwise the spell fails.  On a hit, the target suffers the attacks normal effects, and your weapon is followed by a spectral blade, Dealing force damage equal 1D4 + your spell casting modifier.

 The spell's damage increase when you reach higher levels. The force damage increases by 2D4 at 5th level (3d4), 11th level (5d4), and 17th level (7d4)