Spells Through The Ages – Invisible Stalker

In anticipation of the release of the 2nd Edition of Book of Spells on December 1st, I wanted to look at a couple of high-level spells which are not commonly thought of as problematic, but wind up revealing tricky details if you squint at them long enough. These are issues that I didn't have time to pick up on in the 1st edition, and only on this iteration did I catch them with the finer-toothed comb I was using to untangle stuff. At the end you'll see the specific language I decided to use in the new edition of the book.

Original D&D 

Invisible Stalker: The conjuration of an extra-dimensional monster which can be controlled with merely a word from the Magic-User who conjured him. The Invisible Stalker will continue on its mission until it is accomplished, regardless of time or distance. They cannot be dispelled once conjured, except through attack. Details of the Invisible Stalker itself will be found in the next volume.

The invisible stalker spell was never in Chainmail, so of course we begin with OD&D. One unusual issue with the spell is that you've got writeups for "invisible stalker" in two books: once in the player's book for the spell, and once in the monster book for the creature itself. So in each case we should look in both volumes. Here it is in OD&D Vol-2, Monster & Treasure:

INVISIBLE STALKERS: As previously noted (Vol. 1) these are monsters created by level 6 spells, uttered directly or from scrolls. They are faultless trackers. They follow continually until their mission is accomplished at which time they return to the non-dimension from whence they came. Until their mission is completed they will never vary, and must be destroyed by attack to be stopped, although a Dispell Magic spell will also work. The referee should note, however, that Invisible Stalkers resent missions which entail long periods of continuing service such as guarding a Magic-User for a month, a year, etc. They will then seek to fulfill the letter of their duties by perverting the spirit. For example: An Invisible Stalker is ordered to: "Guard me against all attack, and see that I come to no harm." In order to faithfully fulfill this endless duty the Invisible Stalker will have to take the Magic-User to its non-dimensional plane and place him in suspended animation, and assume this is accomplished whenever a 12 is rolled with two six-sided dice, checking either daily or weekly as the campaign progresses.

Did you catch the glitch? The spell writeup in Vol-1 says that dispel magic does not work, but the monster writeup in Vol-2 says dispel magic does work, so as to eliminate an invisible stalker. I don't see any way to decide the impasse in OD&D on the issue; perhaps taking a consensus from other editions will serve to clarify? The other thing that's interesting in this fairly long monster description (for OD&D) is the bit at the end, where long or ongoing assignments check a 2d6 roll daily or weekly, with box-cars indicating some subversion like carrying away the caster for eternity. This random roll is altered or deleted in future editions.

In the original D&D supplement Swords & Spells, invisible stalker appears in the list of parametrized spells, noting a Range of 1", Area Effect of "1 monster", and Turn Duration of "until destroyed". Note that many other spells in that list, basically the ones that are permanent, are listed as "until dispelled". So perhaps this is a second signal that dispel magic is not meant to work here; or perhaps it's just that destruction in combat takes priority as a more general and expected countering. So it's still unclear.

Expert D&D

Invisible Stalker
Range: 0'
Duration: special
This spell summons an invisible stalker (see page X34) which will follow orders from the magic-user that conjured it. The invisible stalker will continue on its given mission until the mission is accomplished, regardless of time or distance. Once conjured, the invisible stalker can only be sent back by being "killed" in combat or by a clerical dispel evil spell.

That's the spell description; note that it adds the capability of the 5th-level cleric dispel evil to take it out. While it doesn't mention dispel magic by name, if I'm reading the "can only be sent back" passage right, that lower-level spell should not be effective against invisible stalkers (same as the spell description in OD&D). Here's the monster description (stat block elided):

Invisible Stalker
...
An invisible stalker is a very intelligent enchanted monster summoned to this world by use of the invisible stalker magic-user's spell. If the stalker is given a simple task that is clear and can be swiftly completed, it will obey promptly. If the task is complex or lengthy, the invisible stalker will try to distort the intent while obeying the literal command. EXAMPLE: If ordered to guard a treasure for longer than a week, the stalker may take it away to its native plane of existence and guard it there forever.

Invisible stalkers are most often used to track and slay enemies. They are faultless trackers. They surprise any creature that cannot detect invisible creatures on a 1d6 roll of 1-5. They will return to their native plane once they are slain, or dispelled, or have completed their task.

Now once again the monster description says that it can be "dispelled". Most likely this is a carryover from the glitchy OD&D language. But in this case it at least can be interpreted as referring to dispel evil, thereby removing the contradiction. Perhaps.

AD&D 1st Ed.

Invisible Stalker  (Conjuration/Summoning)
Level:  6 
Range:  1"
Duration: Special 
Components:  V, S, M
Casting Time:  1 round
Saving Throw: None
Area of Effect: Special

Expalantion [sic] /Description:  This spell summons an invisible stalker from the Elemental Plane of Air.  This 8 hit die monster will obey and serve the spell caster in performance of whatever tasks are set before it. However, the creature is bound to serve; it does not do so from loyalty or desire. Therefore, it will resent prolonged missions or complex tasks, and  it  will attempt to pervert instructions accordingly (for complete details of the invisible stalker, consult  ADVANCED DUNGEONS  &  DRAGONS, MONSTER MANUAL).  The invisible stalker will follow instructions even at hundreds or thousands of miles distance. The material components of this spell are burning incense and a piece of horn carved into a crescent shape.

In AD&D, for the first time we see the invisible stalker get the detail that it comes from the Elemental Plane of Air. For some reason I find this less awe-inspiring than some unknown alien dimension, possibly Lovecraftian, which is an option left open in OD&D. It does not mention use of dispel magic (so the restriction has been removed?). Note that the range given is 1", as seen first in Swords & Spells (and opposed to the B/X range of 0; a common pattern). The previously-published Monster Manual sayeth thusly:

INVISIBLE STALKER
...
The invisible stalker is a creature from the elemental plane of air, normally encountered on the material plane only due to the conjuration of some magic-user. This conjuration causes the creature to serve for a period on this plane. Invisible stalkers roam the astral and ethereal planes, and if they are encountered there on the elemental planes, they can be dimly seen. Otherwise or unless their opponents are able to detect/see invisible objects, their invisibility causes opponents to subtract 2 from "to hit" dice rolls. Unless slain on their own plane, invisible stalkers are simply sent back to the elemental plane when damage accrued exceeds their total hit points.

The conjuring party retains full command of the invisible stalker summoned until  it  fulfills its duties or is killed. Once set upon a mission, an invisible stalker will follow through unceasingly until it is accomplished. They are faultless trackers within one day of a quarry's passing. They must be destroyed to make them cease an ordered attack. Once a mission is finished, the creature is freed to return to its own plane. The invisible stalker is at best an unwilling servant but will not resent a brief, uncomplicated task. Service involving a period of a week tries the creature severely, and anything longer is  certain to make it attempt to fulfill the letter of command by perverting the spirit of it. This is not to say that impelling the invisible stalker to serve for extended periods is impossible, but the compulsion to cause it to do so fully and properly must be great, i.e. a carefully worded command from a very powerful magic-user. A simple command such as "Follow me, and guard me from any attack," could be interpreted to mean follow at  100'  distance if the invisible stalker had been on duty over a week - or perhaps even if it hadn't been that long, for dealing with such creatures is always a hazard. Similarly, a command to: "Keep me safe from all harm," can be construed by the invisible stalker to mean that it is to carry the conjuring party to its own plane and place them in suspended animation in a secret room in its own abode, thus carrying out its duties to the letter.

Each day of duty which an invisible stalker serves will see a 1% cumulative chance of the creature seeking to pervert the intent of its commands in order to be free of servitude. If no option remains open, the stalker must continue to serve.

Invisible stalkers understand the common speech, but they do not talk any language but their own.

While this block of text has bloated up usual under the unrestrained hand of Gygax in AD&D, parallel to the Player's Handbook spell description, the language allowing dispel magic to work has gone missing here from the monster description. So by default I would assume that most readers of AD&D would conclude that a dispel magic would will work to terminate this spell; and yet it's still not an explicit ruling on the situation one way or the other. Note that the boxcars-on-2d6 method of determining long mission subversion has switched to 1% daily cumulative chance (but unclear if that's meant to start after the first week or not).

AD&D 2nd Ed.

Invisible Stalker
(Conjuration/Summoning)
Range: 10 yds.
Duration: Special
Area of Effect: Special
Components: V, S, M
Casting Time: 1 rd.
Saving Throw: None

This spell summons an invisible stalker from the Elemental Plane of Air. This 8-Hit
Dice monster obeys and serves the spellcaster in performing whatever tasks are set before it. It is a faultless tracker within one day of the quarry's passing. The invisible stalker follows instructions even if they send him hundreds or thousands of miles away and, once given an order, follows through unceasingly until the task is accomplished. However, the creature is bound to serve; it does not do so from loyalty or desire. Therefore, it resents prolonged missions or complex tasks, and it attempts to pervert instructions accordingly. Invisible stalkers understand common speech but speak no language save their own.

The material components of this spell are burning incense and a piece of horn carved
into a crescent shape.

The is pretty much the customary copy-and-paste job from 1E. Here's the (incredibly long) monster description in this edition:

Invisible Stalker

...
The invisible stalker is a creature from the elemental plane of Air. Those encountered on the Prime Material plane have almost always been summoned by wizards to fulfill a specific task.

The true form of the invisible stalker is unknown. On the Material, Astral, or Ethereal planes, the invisible stalker can only be perceived as a shimmering air mass which looks much like the refraction effect caused by hot air passing in front of cold. Invisible stalkers understand the common speech of men, but can not speak it. They can converse only in their own language, which sounds much like the roaring and whooshing of a great wind storm.

Combat: Invisible stalkers attack by using the air itself as a weapon. It is capable of creating a sudden, intense vortex that batters a victim for 4-16 (4d4) points of damage. Such attacks affect a single victim on the same plane as the invisible stalker. Due to their invisibility, these creatures impose a -6 penalty on the surprise rolls of those they choose to attack. Similarly, all opponents who are unable to see or detect invisible foes are at a -2 on their attack rolls. Although they are fully invisible on the Prime Material plane, their outlines can be dimly perceived on the Astral or Ethereal planes.

Invisible stalkers can only be killed on the elemental plane of Air. If attacked on another plane, they automatically return to their home plane when their total hit points are exceeded by the damage they suffered.

Habitat/Society:Little is known about the lives of these creatures on their home plane. It is assumed that they are similar to normal air elementals when encountered there. Those present on the material plane are there as the result of a conjuration by some wizard. This magic causes the creature to serve its summoner for a time. The conjurer retains full command of the stalker until it either fulfills its duties or is defeated and driven back to its home plane. Once given a task, an invisible stalker is relentless. They are faultless trackers who can detect any trail less than a day old. If ordered to attack, they will do so with great fury and will cease their efforts only upon their own destruction or the direct orders of their master. Once their mission is accomplished, the creature is free to return to its home plane.

The invisible stalker is, at best, an unwilling servant. It resents any task assigned to it, although brief, uncomplicated labors may be seen as something of a diversion and thus undertaken with little resentment. Tasks that require a week or more of its time will drive the invisible stalker to pervert the stated intent of the command. Such commands must be carefully worded and come from a powerful wizard. An invisible stalker may look for a loop hole in the command as a means of striking back at its master. For example, a simple command such as "keep me safe from all harm" may result in the stalker carrying the conjurer back to the elemental plane of air and leaving him there in a well hidden location.

Each day of the invisible stalker's indenturedness there is a 1% cumulative chance that the creature will seek a means to pervert its commands and free itself of servitude. If no option is open, the creature must continue to serve.

Ecology: Invisible stalkers are a species unwillingly transplanted to the Prime Material plane. They are slaves whose terms of servitude dominate their brief stays. Those who have been subjected to great hardship, assigned very difficult tasks, or who have faced death at the hands of humanoids, tend to retain a distrust or outright hatred of them. Those that have had an easy time during past periods of service or who are first time arrivals on the Prime Material plane may be easier to deal with. Such feelings may carry over to influence encounters with humanoids traveling in the aerial plane. Anyone who has befriended an invisible stalker in the past will find that voyages through the plane of elemental Air are far less hazardous than they might otherwise have been. Invisible stalkers only obey those who actually summon them and few wizards can be commissioned to summon such a being on another's behalf. Some mercenary wizards have been able to construct the necessary summons onto scrolls that are usable by others. These sell for between 5,000 and 10,000 gp and are very dangerous to use. Even the slightest error can cause users of such scrolls to come to a tragic end.

I guess I never played 2E enough to have read this whole thing. The "vortex of air" attack seems very strange, and not nearly as terrifying as an intimate attack by tooth & claw from an invisible assailant. Perhaps this is the legacy of the Air Elemental specifier come home to roost (elaborated by later designers). Anyway: I can't find any mention of dispel in these blocks of text. So it works normally, by default? Or not?

D&D 3rd Ed.

Summon Monster VII
Conjuration (Summoning) [see text]
Level: Clr 7, Sor/Wiz 7
Components: V, S, F/DF
Casting Time: 1 full round
Range: Close (25 ft. + 5 ft./2 levels)
Effect: One or more summoned creatures, no two of which can be more than 30 ft. apart
Duration: 1 round/level (D)
Saving Throw: None
Spell Resistance: No

This spell summons an outsider (extraplanar creature).  It appears where the character designates and acts immediately, on the character’s turn.  It attacks the character’s opponents to the best of its ability.  If the character can communicate with the outsider, the character can direct it not to attack, to attack particular enemies, or to perform other actions.  Summoned creatures act normally on the last round of the spell and disappear at the end of their turn.

The spell conjures one of the creatures from the 7th-level list on the Summon Monster table below, 1d3 creatures of the same type from the 6th-level list, or 1d4+1 creatures of the same type from a lower-level list.  The character chooses which creature to summon, and can change that choice each time the spell is cast.
...

Invisible stalker N

In 3rd Edition, the invisible stalker spell is eliminated entirely. Instead it is folded into the broader summon monster spells (here at the 7th level); and in so doing it shortens the duration to just 1 round/level, abstracting away the traditional long-term, long-distance, high-risk-and-reward special nature of the creature (similar to a few other spells like conjure elemental). This might be among the greatest sins of the 3rd Edition project; here a highly memorable piece of the game has been safety-bumpered into a total nonentity.

Notice here that the (D) notation for Duration does definitively establish that a dispel magic can be used to end this greatly altered spell. The monster description is now greatly cut down:

Invisible Stalker
...
These creatures speak only Auran but can understand Common.

Combat
An invisible stalker attacks by using the air itself as a weapon. It creates a sudden, intense vortex of wind that pounds a single target on the same plane as the creature.

Invisible stalkers can be killed only when on the Elemental Plane of Air. When performing tasks elsewhere, they automatically return to their home plane when they suffer sufficient damage to destroy them.

Elemental: Immune to poison, sleep, paralysis, and stunning. Not subject to critical hits. 

Natural Invisibility (Su): This ability is constant, allowing the stalker to remain invisible even when attacking. This ability is inherent and not subject to the invisibility purge spell. 

Improved Tracking (Ex): Invisible stalkers are consummate trackers and make Spot checks instead of the usual Wilderness Lore checks to trace a creature’s passage.

I'd say that all of the interesting aspects of the invisible stalker have been eliminated in this iteration. The sullenness, possible resistance, and risk to the caster from literal interpretation of orders are all gone. Actually only the dumbest thing has been retained -- the antiseptic, hands-off "vortex of wind" attack method. Even the tracking ability has been downgraded from cosmically "faultless" to just getting a Spot check. Basically the spell and the creature have been entirely neutered. But at least we know that a dispel magic serves to exterminate them here.

Conclusions

On the issue of dispelling, no edition of D&D clearly and unambiguously stated whether a dispel magic serves to end the existence of an invisible stalker (up until 3rd Ed., when the spell itself was cut from the rules and the much watered-down analog can definitely be dispelled). So after wrestling with this angel for some amount of time, what did I decide to do in the 2nd edition of Book of Spells? Here's my edited text:

---

Invisible Stalker: (Range: 6 inches, Duration: Permanent) This spell conjures an invisible stalker (an extraplanar creature), which is compelled to perform one service for the caster. Once conjured, the stalker can work at any time or distance to complete its task; however, the creature is clever, and will seek to subvert instructions for long missions. It cannot be dispelled, although it can be killed in combat. The spell ends when the stalker completes the specified service.

---

As you can see, I decided to keep the non-dispel restriction, as in the original spell from OD&D. My thinking here is that it increases the threat and the drama from the magical creature -- especially to the summoning wizard him- or herself (if sent after some fighter, thief, or other monster, then it makes little difference). In many cases I would not want an exceptional rule like this, but I think I'm okay with it to distinguish a few spells at the highest level of magic in the game (6th level in OD&D). Furthermore, I actually wanted it here to round out the cases to the theatrical rule-of-3: the new Book of Spells disallows dispel magic against invisible stalker, antimagic sphere, and geas. For purposes of maximal brevity, I did snip out the specific percentage roll for the stalker to subvert its instructions, leaving it fully in the hands of the DM (similar to Dave Cook's version in Expert D&D).

What do you think of that?