Crystal Ward

With the wave of a hand, summon a barrier of spectral crystal intervenes in the course of an attack on you or an allied creature within range. 

Attacks effected by this spell have the damage from the attack reduced by 2d4.

If the barrier fully negated the damage of the attack, the barrier bursts forth with retaliatory force. The attacking creature must make a Dexterity saving throw or take the 1d4 of force damage.

 This spell's damage negated and reflected increases by 1d4 when you reach 5th level (3d4), 11th level (4d4), and 17th level (5d4)