You surround yourself in magic as an ethereal head of a beast forms around you, the look of which you decide when casting this spell. The beast then opens its mouth as it condenses a massive amount of magic, forming a large ball of intense purple energy. You can then decide to use that energy in one of three ways.
You can choose to have the beast launch the ball at a point you can see within a 300ft range. The ball explodes on impact with a detonation equaling that of a sphere with a 40ft radius.
You can choose to have the beast swallow the ball, and then immediately shoot the energy as a 10ft wide beam in a 300ft line.
You can choose to have the beast place the ball in its closed mouth, expelling the energy through its teeth in a 60ft cone.
Any creature caught within range must make a Dexterity saving throw. A creature takes 20d8 force damage on a failed save, or half as much damage on a successful one.