Drago's Deep Calculations

You plunge your mind into deep mathematical calculations, heightening your lethality with ranged attacks, but reducing your capability of reacting to the environment.

For the duration of the spell, ranged attacks are considered critical hits on a roll of 19 or 20. However, you have disadvantage on Dexterity saving throws.

Additionally, at the beginning of each of your turns while concentrating on the spell, you can choose to give yourself a +1/2/3 bonus to ranged attack rolls for that turn. You then suffer a penalty to AC, equal to the bonus you chose, until the start of your next turn.

At Higher Levels. When you cast this spell at a higher level, the AC penalty is reduced by 1 for each level above 3rd.