Arms of Hadar
Invoking Hadar, you cause tendrils to erupt from yourself. Each creature in a 10-foot Emanation originating from you makes a Strength saving throw. On a failed save, a target takes 2d6 Necrotic damage and can't take Reactions until the start of its next turn. On a successful save, a target takes half as much damage only.
Using a Higher-Level Spell Slot. The damage increases by 1d6 for each spell slot level above 1.
Arms of Hadar 5.5e 2024 vs. 5e 2014 edition differences
The 2024 version removes the "Self (10-foot radius)" range, replacing it with "Self" and specifies a 10-foot emanation. It clarifies the saving throw as "each creature in a 10-foot Emanation originating from you," and states "until the start of its next turn" instead of "until its next turn." Damage and scaling remain the same.