Wild Gamble

You channel a mass of uncontrolled magic into an orb. Make a ranged spell attack against the target. On a hit the target takes force damage equal to the amount of energy you channelled into it. You may attempt to channel as much energy into the orb as you can wish but at the risk of losing control and doing nothing.

Roll 1d4, then if you wish roll 1d6. If you roll higher then the previous roll you do that much damage instead.

You may continue to roll die up to 1d12  (1d4 - 1d6 - 1d8 - 1d10- 1d12) as long as you continue to roll above the previous roll.

At 5th level roll 2 of each dice instead. At 11th level the maximum die size changes to a d20, at 17th level roll 3 of each dice instead.