I recently became interested in exploring physical vs. mental spells in D&D 5e and I noticed that there is no true counterpart to Hold Person. Specifically, to my knowledge, there's no spell which result in automatic failures on mental saves (in contrast to Hold Person, which, via the paralyzed condition results in automatic failures on STR/DEX saves).
So I decided to make it. However, I'm not quite sure what should be its spell level.
On its own, its quite weak, however in conjunction with other spells I feel that it could become quite strong. As such I'm currently leaning towards 2nd or 3rd level, in line with Hold Person.
Casting Time: 1 action
Range: 60 feet
Target: A humanoid that you can see within range
Components: V S M (a piece of flesh)
Duration: Concentration, up to 1 minute
Classes: Bard, Cleric, Druid, Sorcerer, Warlock, Wizard
Choose a humanoid that you can see within range. The target must succeed on a Charisma saving throw or lose control of its intellect, reducing it to a beast-like state. At the end of each of its turns, the target can make another Charisma saving throw. On a success, the spell ends on the target.
While in this state, an affected creature's actions are controlled only by their primal instincts. They cannot distinguish friend from foe and any actions that they take must be in interest of their own self preservation. Additionally, they have disadvantage on all Intelligence checks and checks involving social interaction, and they lose the ability to perform complex intellectual tasks like casting spells and speaking.
Moreover, they rely unquestioningly on their senses. As such, they automatically fail Wisdom and Intelligence saving throws.
- I've chosen Charisma as the saving throw for thematic purposes, as I imagine targets needing to stubbornly hold on to their fleeing intellect. This naturally makes it a bit stronger as Charisma saves are more rare.
- I deliberately included "self preservation" language to make it clear that the target doesn't go berserk and attack everything. i.e. the target still acts in their own interests, just without the ability to use reason.
- As with Hold Person, this only works on humanoids, it has a short duration, it requires concentration, the save is repeatable, and nothing happens if the target succeeds in their save.
- For the time being, there's no scaling with spell levels.