How can you destroy a mage hand?

Question

We are playing through B1 "In Search of the Unknown", a basic rules D&D adventure from 1978, using 5e rules. In the module there is a pool of clear acid that has a bronze key clearly visible at its bottom.

If any adventurer falls or leaps within it, certain and immediate death will result. Putting a hand or other body member within it will result in an immediate 2-5 hit points of damage [...] Weapons or other objects dipped into the acid will deteriorate (swords will be marked and weakened, wooden items warped and cracked, etc.) and may even be ruined completely at the discretion of the Dungeon Master

What in the original adventure was an exploration puzzle -- how do you get at the key without being scarred or having your equipment damaged? -- became trivialized when the wizard cast mage hand to pick up the key. Mage hand just says

A spectral, floating hand appears at a point you choose within range. The hand lasts for the duration or until you dismiss it as an action.

It has no hit points and is not an object, so I ruled it does not take any damage and could just pick up the key (which for some weird reason was unaffected by the acid -- I figured bronze was immune to it). The hand cannot even be attacked. This made me wonder: short of a wish, is there any way to destroy a mage hand?

The only things I could think of are Antimagic field to suppress it, or dispel magic to end the spell. Are there any other ways? After all, this is a mere cantrip.

Answer 1

Caveat: Many of these not-quite-objects produced by spells are vaguely defined and considerable DM interpretation is required. We can't use real world physics, so what sense are we to make of a mage hand that can exert a force but is not affected by other forces? If the hand can't pass through the wall of a chest, why can't I hit it with a sword? I think if I were a first level mage with the cantrip, the first test I would want to run is to dip a finger of the mage hand in a graduated cylinder to see how much water, if any, it could displace.

Why destroy when you can obliterate?

You don't have a lot of options. I agree dispel magic is your best bet, as antimagic field will only suppress the hand, not destroy it.

One other possibility is a sphere of annihilation.

The sphere "obliterates all matter it passes through and all matter that passes through it." One could argue that the spectral hand is not "matter", but there is no game definition of "matter" and the hand is a visible presence that can exert a force, so I say close enough. Further, although the hand is "spectral", a preponderance of site users believe that it is so physical as to not be able to pass through a wall or other solid barrier. If the hand can grab things and can't pass through things, I would take it to be 'matter-ish' enough for the sphere.

Further, the sphere presents its targets as either "artifacts", which are undamaged unless they say they are, or "anything else", which is "obliterated" if it fits inside the sphere. I am comfortable with the hand, not being an artifact, being considered "anything else" when given nothing more than a dichotomous choice.

or disintegrate?

Mathaddict, in a comment, suggests the disintegrate spell, which says (emphasis mine):

A thin green ray springs from your pointing finger to a target that you can see within range. The target can be a creature, an object, or a creation of magical force, such as the wall created by wall of force...
This spell automatically disintegrates a Large or smaller nonmagical object or a creation of magical force.

The hand doesn't explicitly tell us that it is a "creation of magical force", but it is certainly a magical creation. For that matter, wall of force doesn't literally say it is a "creation of magical force" either, it just says "an invisible wall of force springs into existence". If wall of force is specifically called out as affected by disintegrate, then it depends on how broadly you want to apply disintegrate's "such as" clause. As a DM, I would say the hand is close enough.

To bookend my opening caveat, these magical effects are poorly defined. After Mathaddict's suggestion, I looked up disintegrate and wall of force. But wait - if disintegrate can only target things you can see, and the wall of force is specifically invisible, how is it that disintegrate works on wall of force? Although that question was new to me, I'm not the first one to have asked it.

It is the job of the DM to decide how to rule in these cases - hopefully with an eye to either creating a world of logical rules, or one in which magic is always a mystery. Whatever you rule, it should be intentional and support your world-building efforts.

Answer 2

Actually, you do not need the heavy artillery (Antimagic Field, Dispel Magic, Wish) or DM power, you may just exploit the limitations of this cantrip.

Put the key more than 30 feet away from the boundary of the pool.

The Mage Hand cantrip has the following ending condition:

The hand vanishes if it is ever more than 30 feet away from you or if you cast this spell again.

So, if the acid pool has the right dimensions, e.g. radius 30 feet and 5 ft. of depth¹, the key lying at the very bottom cannot be reached by this cantrip.

Since you stated that the acid is limpid and let see the key clearly, such dimensions do not pose any problem.

Make the key weight more than 10 pounds.

Mage Hand has some limits (emphasis mine):

The hand can't attack, activate magic items, or carry more than 10 pounds.

If you make the key really heavy, more then 10 pounds, you are done. Or even attach it to something heavy².

If you really want to use heavy magic stuff, you may consider Dead Magic zones, or for more funny outcomes Wild Magic zones.

If you are playing in the Forgotten Realms settings, there are some zones (SCAG, page 19) that are disconnected from the Weave:

Dead Magic. In rare areas of dead magic, the Weave is absent. Not only do spells and magic items cease to function, but even the supernatural abilities of creatures that are innately tied to the Weave might fail as the knot of the Weave they carry with them unravels.

The pool, and only the pool, can be one of these zone, where magic cannot happen. If you are not playing in the FR settings, you may borrow this particular environment and place it in your world.

Another zone is the Wild Magic one:

Wild Magic. In an area of wild magic, the Weave becomes "tangled," spontaneously forming its own constructs and resulting magic. It also tends to twist the constructs of the Weave created by spellcasting, causing unexpected results.

This could add a little twist on the spellcasting, providing unusual results. As a personal experience, a couple of times I used these zone, using the Wild Surge table from the Sorcerer subclass to determine the outcome: me and my players enjoyed this a lot.

---

¹ Recall that there is always also the 3rd dimension...

² Who does not use a cannon ball as a keychain?

Answer 3

Forced Movement

One more RAW way to destroy a Mage Hand is to move the caster 30ft away from it, using any of the many methods of forcing movement.

The hand vanishes if it is ever more than 30 feet away from you

You can use your action to control the hand... [and] move the hand up to 30 feet

The hand can only be moved by an action from the caster, so if you can reliably move the caster 30 ft before they can spend an action to move the hand, you can destroy (or at least unsummon) their Mage Hand.

Eddymage's answer briefly mentioned this condition, though only as a way to prevent the use of the cantrip through distance rather than a way to destroy the hand itself.

A few examples off the top of my head: Banishment, three hits from a Warlock's Repelling Blast, or good old-fashioned grapple-and-drag from a fast character like a Tabaxi or a Monk.

Caster Death

Also, to address a comment the OP made: "even killing the caster will not work, as it has a 1 min duration"

Arguably, killing the caster should dispel the Mage Hand. When the caster dies, they cease to be the caster and become a corpse, an object. At this point you could argue that the hand is more than 30ft away from the caster, who has ceased to exist.

Answer 4

The rules don't give you an answer . . . .

The rules don't tell you how to destroy mage hand. You've named the obvious: dispel magic, antimagic, and, of course, wish.

. . . . but of course the DM can.

In this particular case, if you don't want mage hand to work, you've probably already thought of many options. Some I've thought of:

• It just doesn't work
• There's a diffraction effect, and grabbing the key requires some kind of check
• There's an antimagic barrier in the water
• The pool is more than 30 feet deep (or more than 60 feet wide)
• It works, but the caster magically takes the damage

None of these are unreasonable.

Of note

You mentioned this was originally a 1e adventure. AD&D was my introduction to D&D, deep in the last century. I do not recall a mage hand spell, or even cantrips. Admittedly, it was a long time ago. Sadly, among my many poor life choices was deciding to get rid of my books some time late last century; all I can say is like so many bad decisions it made sense at the time. Anyway, I have the AD&D Players Handbook in PDF, and there is no such spell.

Point being, it seems perfectly reasonable in converting the adventure to 5e, to take into account differences in the editions, and make the puzzle somewhat of a challenge by not allowing mage hand to just defeat it.

As ShadowRanger points out, 1e had unseen servant, which could (presumably) also defeat the puzzle. Still, that's a different thing. In 5e mage hand seems a very likely cantrip for any caster to take who has it available; it has been in our games. I very much recall the agony of spell selection in AD&D (even after all these years!), because AD&D didn't have the flexibility of how 5e spell slots work, so choosing to take unseen servant was expensive.

So . . . mage hand, generally useful, can be used over and over, vs. unseen servant, costs a precious 1st level slot and can only be used once. Two different costs, for sure.

Even so, if I were running it, I might make the unseen servant take the damage from the acid . . . that the acid is magical doesn't seem a huge stretch.