You as a being of magic have gained resistance to it. You have advantage on Intelligence, Charisma, Wisdom saves against magic.

Your body turns to pure arcane energy for 1 minute, during that time your gain the following benefits.

1- you gain an energy beam attack dealing 1d12+ spell mod force damage range of 120ft, you are able to shoot two beams as an action. You gain an additional beam at 5th level. At level 7 up the damage to 2d12 per beam

2- gain a shield of arcane energy crackling around you, the shield absorbs 3 times your spell save dc

3- as a reaction you may explode your shield dealing damage equal to the remaining absorption.

At the end of the transformation, you gain 2 negative levels of exhaustion. You may use this trait a number of times equal to your proficiency bonus. 

You as a being of arcane power gain +2 and +1 to ability scores