Voidwind

A sudden stream of radiation erupts in a line 60 feet long and 10 feet wide. The blast originates from a point you choose which you can see within range and is aimed in a direction you choose. Each creature within the line must make a Dexterity saving throw. On a failed save, a creature takes 4d8 radiant damage, or half as much on a successful save. If you roll an 8 on any damage die, you can roll an additional d8 and add its damage to the total, rolling again if this die is also an 8, and so on. You can roll a total number of damage dice for this spell equal to twice the number of damage dice you initially rolled. Additionally, a creature that failed its saving throw is pushed back by 5 feet for each die which rolled an 8. At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the initial damage increases by 1d8 for each slot level above 3rd.