Viola's Blood Curse: Blood Splinter

You conjure a jagged bolt of solid blood to fire at a creature within range. You make an attack role against the target. On a hit the target takes 3d10 necrotic damage. On a critical hit, the bolt splinters off and hits another target of the caster's choice within range inflicting half of the damage rolled on the damage dice. If there is no other target in range then the original target takes the damage on top of the critical damage it already withstood. If this attack reduces any creature that was hit by the curse to 0 hit points then the bolt also splinters off doing half of the damage rolled on the damage dice to a nearby target of the caster's choice.  

At Higher Levels When you cast this spell at 2nd level or higher you create one more bolt for each spell slot above 1st level.