Energy pulse

The caster takes up his/her arm and stretches it out pointing at a target with an open hand then a flash of energy appears entering into the body of the target, when the nergy tries to get out it causes damage or potentially loss of a limb.  Make a ranged spell attack,  on a hit the target takes 12d8 force damage and is pushed 20 ft back with a loud boom that is heard up from 600ft of the source, the target has to make a con saving throw  or lose a limb or head from the table below. (Losing a limb has the effects from lingering injuries in the DMG.) The lost limb can be restored by putting it to the part of the body at wich it was torn off then casting greater restoratsion.

1d20 

1-5 The target loses a leg .

5-9 the target loses a foot.

10-14 the target loses a hand.

15-19 The target loses an arm.

20 The target loses it´s head and dies unless it can survive without it´s head.

At higer levels: For each spell slot above 8 that you cast this spell for the damage increases by 1d10