A beam of concentrated arcane force lashes out from your hand. The beam is 1 foot wide and 30-feet long.

Roll 5d4 and add your spellcasting ability modifier. The total is the pool of how many hit points of creatures this spell can affect this turn.

The first creature in the line must make a Dexterity saving throw. On a failed save it takes force damage equal to remaining damage pool, or half as much damage on a successful one. A creature can choose not to take this saving throw if it wishes, taking the full damage remaining in the pool if it does this.

If a creature is reduced to 0 hit points by the beam then it stops taking damage from the beam at 0 hit points and doesn't take further damage from the beam this turn. Subtract the damage taken by the creature from the damage pool. If the damage pool is reduced to 0 hit points then the beam stops for this turn, otherwise the above process repeats for the next creature in the line.

At the start of each of your subsequent turns the pool refills, and you add 1d4 + your spellcasting ability modifier to the total pool of damage, as well as increase the length of the line by 5 feet. You can create a new line of force as your action on any turn until the spell ends.

For the duration, a mote of bright light shines in your hand. It starts by shedding bright light in a 5-foot radius and dim light for an additional 5 feet, but the bright light and dim light each increase by 5ft every round.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the initial damage increases by 2d4 for each slot level above 5th.