I've been going through the posts on feeblemind, but haven't found one that explains, other than what is specifically mentioned in the spell, exactly what can be done while under it's effects.
It is clear that a creature can't cast spells, activate magical items, understand language, or communicate. It is also clear that they can identify friends, follow them and "protect" them. The spell does not specify any other effects, but…
The spell drops the character's INT and CHR to 1. This leaves a character with the intellect of a bug or lizard. The one thing the spell does not go into detail over is what that means for the character.
Is there anything RAW that indicates what a character/creature with an INT of 1 can actually accomplish?
In my mind, any character would be able to avoid attacking friends (it says so), but when given multiple baddies, would the player be able to specify which baddie they attacked (with the player choosing the most opportune target obviously)? Or would a random roll be appropriate? Or, if already attacked by a baddie, would it be appropriate to tell the player "you are fixated on this creature, since it hurt you?"
What about proficiencies with weapons? To me, an INT of 1 means they can't recall how to use tools/weapons, as this is based on memory. that wouldn't necessarily preclude the use of them, but it would remove the prof. bonus.
As for character abilities, I don't think an INT of 1 would necessarily preclude their use. I do think it would be situational, based on the ability.
Am I reading too much into this? Is this all in the domain of "It's the DM's call?" Should I stick with "the spell doesn't specifically forbid it, so it's good to go?"
Best Answer
Does a feebleminded creature lose proficiency in weapons?
There is nothing in the spell that specifies you lose proficiencies with weapons. There is no requirement on proficiencies that say you must have a minimum intelligence or charisma score.
Since the 5e adage is that "things do what they say they do", it is not RAW that a creature under the effects of feeblemind lose proficiency. If you're thinking that proficiency in a tool or weapon is memory, I would respond that it is muscle memory.
How does a feebleminded creature decide what to attack?
As the spell specifies "The creature can, however, identify its friends, follow them, and even protect them." (PHB 239), it seems like identifying friend and foe is innate. If you can protect a friend, you need to know what threatens a friend.
The last source of an attack on you or a friend seems like a clear threat.
The healer of that threat might be less obvious and would take some intelligence to deduct that they are a defacto threat.
Can a feebleminded creature use character abilities?
Intelligence and Charisma based abilities would seem out the window. If not specified in RAW, being unable to communicate makes persuading someone seem unlikely.
Physical abilities, again, appear innate. Having low intelligence doesn't stop you from being strong or having quick reflexes.
Supporting Examples
So a creature with 1 INT can be somewhat proficient in stealth.
So a creature with 1 INT can be somewhat proficient in perception.