Recently, my players faced off against an enemy spellcaster. During the fight, the barbarian stated that it was his intention to grab the spellcaster in a bearhug, pinning his arms to his sides to prevent him from casting spells with somatic or material components (unable to reach his component pouch).
I'm pretty sure that this doesn't fall under the grapple rules, because grapple has no rules other than preventing movement. Normally when something is outside the rules, I would fall back on the standard adjudication cycle:
- The DM describes the environment
- The players describe what they want
- The DM narrates the result of the character's actions
However, this got me thinking about the "scope" of 5e combat. Certain actions, such as Called Shots are outside the scope of 5e combat; that is to say, they try to go beyond the inherently abstract nature of AC, HP and attack rolls to simulate aiming at specific body parts, which the game was not designed to do. Thus, it seems the correct decision when a player wants to "shoot him right in the eye with my arrow" is to simply say "the system doesn't support that" rather than rely on the standard adjudication cycle.
Like a Called Shot, this arm-pinning ignores the abstract nature of combat by targeting a specific part of the body, shutting down an opponent without reducing their HP. This becomes more blatant if we imagine the barbarian had said "I want to break his arms so he can't cast spells." Furthermore, one could imagine an analogous case in which the same maneuver is used to prevent a melee combatant from using their weapons.
On the other hand, creative play should be rewarded, and "doing anything you can think of" is one of the main draws of D&D over, for example, video games. If the scope of combat is constrained too tightly, combat devolves into "pressing the attack button" over and over.
My question: which case should my player's desired action fall under? Is trying to pin an opponent's arms within the scope of 5e combat? Should it be adjudicated via a contest of some sort, or by saying "the system doesn't support that"?
Best Answer
It's not in the rules, but DMs have the latitude to allow it.
As you point out, I couldn't find anywhere in the rules to support an action like that. However, the system allows for DMs to make judgments about whether an action is reasonable/possible, as well as how difficult it is (PHB 192):
This specific instance is probably balanced.
Thus, it's up to you as the DM to determine whether this specific case should be allowed. More specifically, we need to ask, "If creatures are allowed to do this, would they always do it?"
From a theorycrafting perspective, it seems roughly balanced. The effects of pinning a caster's arms (or any character's arms, really), is roughly comparable to Hold Person, which is a second-level spell. We can take a cue from Hold Person, and say that if we want the effect to last multiple rounds, the grabbed character should get an opportunity to escape every round (as if from a grapple). The rest of the balance is probably a wash, because such a pin prevents the attacker from doing anything else, but they can do it for free.
We can also look to the grappler feat, which does something similar (PHB 167):
Consider that you're allowing any character to take the benefit of this feat for free, and that the effect you're trying to create is actually more powerful than this feat. I'm personally OK with this, given that my players don't really use feats, but it's ultimately up to you and your players.
I have used a similar rule in actual play, and it seems to be a bit underpowered compared to other possible actions. I had a few of my NPC characters try to grab and pin the PCs, both to prevent them from escaping and to incapacitate them. I required my NPCs to initiate a grapple with one action, and then make a contested strength check to pin them with another action. Because the process costs two actions, allows for two "saving throws", does no damage, and still permits verbal-only spellcasting, its opportunity cost is very high--imagine the damage that a strong creature could do in two rounds! Additionally, once they are pinned, the grappler cannot do anything else, which effectively takes them out of the combat. While such an action was appropriate for the situation, I cannot imagine a smart combatant wanting to do this with any frequency.
However, if you do include this rule, you should remember that it will affect your future combats. It might not make much sense to try this move if there are lots of enemies, but it can completely shut down a combat with a solo spellcaster, if they ever move within melee range. It will also open up this option to enemies restraining the PCs, which they might not be super happy about.