Death`s Caress

The following spell name is directly taken from Blizzard, but I owe nothing related to World of Warcraft nor Blizzard. I merely wish to bring the spell to the masses. All rights go to Blizzard Entertainment.

Creator note: This spell might feel extremely powerful, and probably is, so make sure to consult your DM before use. I made it with the Death Knights from the World of Warcraft universe in mind, therefor making it powerful.    

You point at a creature within 60 feet, sending a small horde of necrotic tendrils towards the target. All creatures within a 5 feet wide line on the path toward the targeted creature must make a Dexterity saving throw. Failing this causes 6D4 either Necrotic, Cold or Force damage and knocks it prone. Succeeding the saving throw causes only half damage. Upon reaching the main target, said target must make the same Dexterity saving throw. Failing this causes the target to suffer 20 Necrotic, Cold or Force damage and knocking the target prone. Succeeding the saving throw causes only half damage.

At Higher Levels. Increasing the damage dice by 1D4 against those on the path towards the main target, and 2 against the main target for each spell slot used above 2nd level.