So I'm doing a encounter in my game where my players are going to face off against a hag in a coastal cave and as a part of this encounter they eat human flesh and I have a couple of questions about this encounter:

1. What should the corpse soup do to them? I'm running it like the Hag is illusioned as a normal person just offering then soup and is giving them a corpse soup to cause them suffering so it should specifically hurt/poison them in some way besides mental scars.

2. What other creatures should I run with my Hag? I'm afraid my party will end up taking out the the hag in 2 turns and want some smaller creatures to stretch out the fight. It is set in a coastal cave so I need creature that would logically be there.