Saturday, May 31, 2014

Towards a Taxonomy of 'Trick' Monsters

A discussion of trick monsters
WOTC's new Owlbear, lovely plummage, same bloody beak
Occasionally one hears table-top RPG players discuss trick monsters, usually with a bit of disdain or annoyance.  Things like Nilbogs (with their reverse everything mechanic) and the various monsters that conceal themselves as treasure or harmless dungeon dressing (mimics, trappers, lurkers above) are classic examples of ‘stupid’ or ‘silly’ trick monsters and get a share of disgust and annoyance.  Yet the trick monster is the mainstay of computer RPGs these days (especially the more action oriented ones) and can be a great deal of fun.  Basically a trick monster is an adversary that the players must think up a special way of defeating beyond simply squaring their avatar’s shoulders and having some luck with the dice and this provides the basis for a fun encounter.
Trick monsters aren't a bad thing, it feels good from the player side of things to defeat a monster that does something tricky, either through figuring out a puzzle or because it’s at least different than doing things the standard way.  The key to making a good trick monster is to make it something that either provides a warning, or a context that is itself a warning.  How subtle or overt these warnings must be relates to the players and the GM in question.  Still a trick monster without warning or worse one that gives false clues, is not fun - these are gotcha monsters as opposed to trick monsters.  Even the Nilbog isn’t like this despite it’s silliness, you cut it with a sword and it looks healthier, meaning there is a quick way to figure out what's special about the horror. A gotcha monster is an enemy where the trick isn't part of the story, it's aimed at the players with the goal of tricking them into making mistakes. For example, a fire elemental that is healed by cold and water attacks but harmed only by lightning would be a rather nasty gotcha monster both because the clues about it (unless it’s a made of icy blue flames, but even then) are the opposite of its trick, and because the trick of hurting it with lightning is entirely concealed.

Special abilities are important, and really a very necessary part of good monster design.  They become more important the higher level the party is, both because the players will be well acquainted with regular combat, and because at higher levels combat encounters often take a lot longer.  Special abilities, either by making a monster susceptible to certain tactics or by making the monster more dangerous make combat quicker and more dangerous.  Even at first level monster special abilities are interesting and build setting.

1) Surprise/Concealment/Ambush – From a murderous animate carpet, to goblin huntsmen with a concealed blind this is one of the simplest and most effective tricks. The enemy will spring at the characters and get a free attack or two unless they are detected.  While players are likely to find monsters that are perfect the simulacra of flooring silly or unfair, they are unlikely to complain about monstrous felines that drop from the trees or bandit snipers.  Some warning is perhaps, but not always, appropriate - with a plain ambush it’s not really necessary.  Trappers and Lurkers above (who compound their ambush with delayed death) and hide in plain sight might need a bit more warning of their existence, and context.  Certainly something like the animate carpet is a better example than the fake stone Trapper, as its presence is advertised as being different from the rest of the dungeon.  No player can seriously complain if after having battled an animate stool and gang of brooms in the wizard’s pantry, the rug in the hall rises up to smother her character.

2) Backstabbing – An underutilized variant of the ambush creature, this is some monster that mimics the thief’s traditional ability to strike unsuspected with increased accuracy and for a large amount of damage. This makes ambushing monsters even more trap like, as unless detected they can suddenly kill a party member.  Likewise a backstabbing ambusher (again like a thief) need not be as tough as another creature to be scary, their normal attacks and defenses can be relatively weak as the initial attack is so effective.   The increased deadliness of these creatures means that removing the sense of unfairness from them is best done by making them detectable and perhaps providing warning.  Even something like an invisible stalker (underused is the invisible phantom monster) should appear in context – in a wizards laboratory or a shrine to an evil god of the wind for example and perhaps provide subtle signs that it’s nearby (a strange Predator like blur even).

3) Spell Use/Abilities – Insane warlocks make the best enemies.  Like the backstabbing monster, spell casting enemies turn character abilities back on the party, specifically the extremely dangerous powers of magic.  Spell casters are fun enemies, because the mechanics for spell casting are well defined and clear to the players.  Spell casters rarely need warning, as they are an enemy the player understands.  The more a monster deviates from the traditional Player Character spell caster’s weakness to melee combat, the more dangerous it become, and the more some sort of warning or context is appropriate.

4) Delayed Damage/Multiplying Damage – A monster that telegraphs attacks for more than a round.  Generally this is some sort of obviously dangerous or even lethal attack. More often than not the delayed attack is combined with some other mechanic, such as the swallow and suffocation of a purple worm, or even the bear hug attack of an owlbear.  Both mechanics encourage certain combat choices and disfavor a straight forward melee approach.  These mechanics put whichever character directly engages the monster or seeks to draw its attention in the greatest danger.  For example, a fighter who bravely stand up to the owlbear will quickly be picked to piece by its bearhug and beak.  They thus demand a change in tactics to defeat.  The owlbear requires harrying and missile attacks, but it would be just as simple to create a creature that required melee engagement, say a modified version of the manticore.  These mechanic are nice because as long as they are clearly evident in the creature they don’t need any explanation or warning beyond the encounter itself.

5) Doesn’t Attack Hit Points – The poison spider is the easiest example of this, as is anything that requires a saving throw.  This is a great mechanic, perhaps even the central trick mechanic. Like the above delayed damage mechanic it makes the players adapt their tactics. The classic variation on this attack is level draining undead, which do small amounts of damage, but not only both permanently penalize battling them, but kill in a set number of hits, regardless of HP.  Beyond saving throws there is the option of attacks that do direct damage to statistics.  I like this option, especially for magical creatures because it not only makes the players change their tactics, it puts different characters at risk.  When an attack damage Int and bypasses armor, the magic user becomes the character who should stand toe to toe with it while the party brute takes on a supporting role.  These attacks are tactical and as long as they aren’t instantly deadly or entirely obvious (avoid the venom dripping from the giant scorpion tail) they don’t need a great deal of warning, only context.

6) Breath Weapons – Breath weapons have a special place as they are the nearly unique power of old school dragons.  Or at least that’s what I mean by a ‘breath weapon’ – a devastating attack that does damage based on the existing hit points of the monster. This emphasizes a certain kind of tactics and makes a dragon an incredibly dangerous hit and run opponent. This mechanic is neat because it works as a meta-game element as well, players know what a dragon breath attack does and are afraid of it, they know its specific limitations and powers as a nearly unique mechanic.  As a pretty tactical ability, this is something that is a fair attack as long as it’s contextually sensible.

7) Restraint or Removal – The Monster can remove or otherwise incapacitate its enemies.  Paralysis, swallowing attacks or magic are examples of this kind of attack.  By reducing the player’s options and numbers this attack is dangerous, but it isn’t lethal like a save or die poison, so it can be used much more easily.  It also has the advantage of complicating defeat, as most players are unwilling to leave living companions behind.  Another cool element of this sort of trick is that the victims are captured rather then slain, meaning that even a total party defeat isn’t the end of the game.  Again as a tactical mechanic that is more limiting then completely destructive, this doesn’t seem to be a trick in need of a great deal of warning.

8) Automatic Damage to Attackers – A creature that either reflects certain kinds of attacks or does damage per round to anyone who engages it in a certain way.  Classically this is some sort of spell reflection, but it would work well as a cloud of stinging midges or some sort of arcing lighting that harms ranged attackers.  Since the results here are damage, and usually either the damage that the players own attacks would do, this isn’t an extremely deadly special ability, but it has the ability to make surprise attacks, a backstab or an unexpected lightning bolt very deadly to the players.  An aura attack is likely best warned of with monster appearance.

9) Destroys Equipment – The Rust monster is almost universally hated by D&D players but it’s a rather sound and reasonable trick monster.  Nearly harmless, except for its ability to melt metal equipment – there is perhaps nothing glorious about taking off one’s armor and beating the rust monster to death with a ten foot pole, but it clearly changes the dynamic of combat.  I suspect the annoyance at this sort of creature is player hatred for losing equipment.  This seems a bit odd in a game that is traditionally focused on resource allocation and attrition, but my anecdotal experience is that (like level draining) players strongly dislike losing their equipment.  A similar effect would be a monster that steals the spells out of a caster’s mind.  I am hung up about how warned about these monsters the players should be, mainly because they are so reviled by players.  Yet, it may be that in a context where the creature makes sense, some sort of decay spirit rather than a weird propeller bug creature, it’s sensible enough that the danger can be anticipated and fair.  

10) Lingering Effects – Mummy Rot, a lethal disease that needs two high level spells to cure is pretty harsh, but the mechanic is sound.  I’m not sure how useful it is, as the delayed effect doesn’t really impact the encounter and only matters if it’s something that can be incorporated into the larger campaign.  As something that is more of a campaign effect, this sort of trick is something to play carefully and think out beforehand.  Warnings clues and signs might be appropriate, but since this sort of trick seems mostly campaign focused it largely depends on the campaign.  It’s for this reason that the I wouldn’t use lingering effects for incidental monsters, as tempting and authentic as it might seem for giant rats to spread disease, anything that requires figuring out disease rates and questing for cures should be planned out beforehand.

11) Special Immunity – Classically this means something like an immunity to weapons, typical of undead or spectral creatures.  Other examples exist, immunity to elemental attacks or magic general for example, even the ability to snatch missiles out of the air.  These classic defenses are good, because at low levels they make monsters terrifying and at high level they are a way of limiting the effectiveness of excessive henchmen.  In general if the defenses are obvious, there’s nothing wrong with this, but when the defenses are concealed it’s rather frustrating and should be avoided.

12) Possession – Monsters with special abilities that take possession of an enemy are really scary.  The danger of these monsters is immense, as to defeat them the party may have to fight themselves.  Ghosts are the most terrifying example of this, specifically their near immunity to damage, their powerful aging attack and the ability to possess characters with magic jar makes them incredibly powerful, even against high level PCs.  One of the other interesting things about creatures with possession ability is that most players won’t attack their friends once they are possessed, so the party is often forced to negotiate with the possession monster.  Clues and warning are pretty appropriate simply because the danger of the trick.

13) Regeneration – Trolls regenerate, that’s what every D&D player knows about trolls.  Regeneration, or perhaps damage reduction, are a neat special defense.  It’s also something that can bring a monster back again and again, a sort of anti-immunity effect.   In general regeneration is pretty straightforward if it’s a healing per round effect.  More complex regeneration is a power that keeps returning until something is special is done to kill it, a special item destroyed or weapon used.  Since regeneration makes monsters only marginally tougher, it’s something that isn’t especially worth providing clues for, though if there’s a hidden secret that provides the only way to destroy a powerful enemy, that is obviously a different story.

14) Temporary Immunity – Total immunity isn’t a reasonable trick, I’ve only seen it in the worst sorts of railroad modules.  At the same time temporary immunity on a strict timeline or with conditions is a rarely used trick.  A monster that is immune to attack for the first three rounds, and it becomes especially dangerous, but in a fairly interesting way.   One could also have a monster that is immune for a few rounds based on a certain conditions.  This is something would look require a pretty good warning, after all, bosses in old video games flash red when they are about to do a special attack.

15) Fairy Tale Defenses – Fairy tale monsters are fun, creatures that have strange special abilities, specifically defensive abilities, that can only be overcome with something strange.  A tough monster that can be defeated only by a unique weapon or item, cats for example.  This sort of trick requires a bit more planning, and might be best for a legendary creature, requiring some kind of in game preparation.   I think this is an underused trick, but it’s one that is could easily be overused, and so worth saving for important campaign enemies.  

I suspect this list isn't all inclusive, but the point of the list to look at the special abilities of monsters as a means, to recognize that the mechanical aspects of monster design can be viewed like any other mechanic and should be considered from a perspective of how they effect play.  Despite this, I don't mean to suggest that a GM should look only at the way a special ability will effect play, special abilities are intrinsic to certain monsters and their identity.  Good monster design means making sure that the monster has a logic, and if that logic demands it spray acid, it should spray acid.  Special Abilities that stem from monster identity are good because they provide an intrinsic clue, something that the players can break down and base their plans around.


  1. This is an excellent road-map for creative monster design that deserves to be read far and wide. This is very well thought out. You raise quite a few excellent points and pointed out a thing or two that made even such a grizzled and scarred veteran of monster-making as myself sit back and go 'hmmmm...' I plan on adding this to our reference section of the Vermiform Appendix once I get it ready to post once and for all.

    My only quibble: check out the first section, there seem to be a couple of spots where things got lost or dropped. Other than that, it's practically perfect. One of the best reads I've run across in months, if not longer.

    1. Thanks, I'm glad you liked it. I fixed up some of the missing chunks.

  2. Impressive! Fun read. Bookmarked.

  3. Good overview. Looking back over my Weird Adventures monsters, I seem to like "liingering effects" and monsters that "don't attack hit points" quite a bit. Who new?

    1. Lingering effects appeals to me as well, but I realized how hard it is to use without subsystems already in place. It may be different in non-D&D systems or if you go simple with something like "cat scratch fever, causes -2 base HP and unwholesome gyrations that result in a -2 to party encounter checks until character takes to bed for a session." is making players play their henchmen for a session cruel or cool?

  4. I thought this post was really good so I added a link to it on my Best Reads of the Week series. I hope you don't mind.

    1. Not at all @Charles Akins, I like anyone linking to my stuff, and am I thought the post was good as well - the discussion on it from necropraxis and gameswithothers got me thinking about how to model certain wargaming artifact abilities (those that depend on strict spatial measurement) for entirely abstract play. Mainly dragon breath and its mundane friend the cannon.