The text is unclear to me.
Tendrils of dark energy erupt from you and batter all creatures within 10 feet of you.
I assume I’m a creature within 10 feet of me, so am I also a target of this spell? Some other spells say "all other creatures", and since this does not it feels like it would make sense to include the caster. But on the other hand, if this spell always damages the caster it seems like it would say something explicitly about that.
So, if I cast Arms of Hadar, do I have to make the save?