Creating Random Universal Nasty Creatures Heuristically

Introduction: How to make really cool, unique monsters for your RPG of choice

These rules are pretty much game independent, you should be able to figure out what will work in your own game system.  Damage is given in terms of percentage of normal human hit points done on a average hit.  Magical spell suggestions and some spell effects are based on GURPS rules...which are of course...universal...so you should be able to use them with any game system.

These tables were originally created for use with the world of Domibia, where magical fumbles create monsters by channeling magical energy into the nearby environment.  The worse the magical fumble, the greater the class of monster that would develop.  It is hard to quantify just which table should be used if you are not using the Domibian magic system.  A Class 1 monster could theoretically be more powerful than a Class 6 monster, with the right rolls.  In general though, the greater the class, the more likely the monster will be some sort of grotesque blimp, laying waste to all in its path.
Disclaimer:  The motifs that I have translated into random tables were described and discussed in the unfortunately out-of-print GURPS Fantasy Bestiary where they were given no game descriptions.  I have added all those.  The original info just contained "real world" mythological motifs, which I distilled into these tables and game mechanics.

Magical Fumbles Table

Using this stuff in game play

Sometimes it seems that the results aren't very impressive, but don't discard them without giving some serious thought to how the result could be intelligently played.  For example, in the Domibian campaign I ran for some time the characters were given a landholding on the outskirts of the small kingdom they lived in.  When they moved in they heard from local farmers that the area was menaced by a black-winged wolf with glowing red eyes and the ability to produce clouds of smoke.  The locals would leave offerings of food for the beast which was called the Baleful Hound of the Twin Pines.  It was actually a rather plump dog that had near-human intelligence, could speak, and had large owl type wings on its shoulders.  It could cast two spells, Charm Person and Darkness (sorry, this was a 3rd Edition D&D game...I went over to the dark side for a year or so).  With these rather unimpressive abilities I was able to have the characters running scared for several game sessions.  They were setting traps, posting guards all night and generally fearing this awful beast.  Even though they never saw glowing eyes, smoke or anything demonic about the dog they still assumed he was really tough.  Of course they could blame that on the farmers, but what farmer is going to say that he was menaced by a fat collie with wings?

More examples

Motif Type & Number

The tables below are for determining random monster motifs, both quantity and type. Roll 3D6 on the row corresponding to the class of monster than was called for on the Fumble table. Find the range that your dice roll falls within, beneath that number is a result in the form of a dice roll. That dice roll is used to generate the results on the following table, which will give the type of motif(s) to be rolled for. All results that are lower than the final roll are also implemented. Ex: If you had a Class 6 creature and rolled a "13" you would have one motif rolled with 7D6 but you would also have one 6D6, 5D6, 4D6 3D6 and 2D6 motif, thus giving the creature a total of 6 motifs.

Roll 3d6

Type of Motif

(roll the number of d6 indicated by the results above)

 Monstrous plants are listed separately at the bottom.

Random Monster Motifs

a) Animals that Curse or Bring Luck 
Roll 2D6
2= Curses it's slayer (roll at +4) Blesses those who help it (roll at +4)
3= Curses it's slayer (roll at +3) Blesses those who help it (roll at +3)
4= Curses it's slayer (roll at +3) Blesses those who help it (roll at +2)
5= Curses it's slayer (roll at +2) Blesses those who help it (roll at +1)
6= Curses it's slayer (roll at +1) Blesses those who help it (roll with no modifier)
7= Viewing is good omen and it curses it's slayer. (roll on next table with no modifier)
8= Viewing is bad omen and it curses it's slayer (roll at +1)
9= Viewing is bad omen and it curses it's slayer (roll at +1)
10= Viewing is bad omen and it curses it's slayer (roll at +2)
11= Viewing is bad omen and it curses it's slayer (roll at +3)
12= Viewing is curse (roll with no modifier) and it curses it's slayer (roll at +4)

Roll 1D6 (plus modifiers)
1= 1 point Curse -or- 1 point Blessing
2= 1 point Curse -or- 1 point Blessing
3= 1 point Curse -or- 1 point Blessing
4= 2 point Curse -or- 2 point Blessing
5= 2 point Curse -or- 2 point Blessing
6= 3 point Curse -or- 3 point Blessing
7= 3 point Curse -or- 3 point Blessing
8= Unluckiness -or- Level 1 Luck
9= (roll 1D6) 1-3= Cursed, 4-6= Jinxed -or- Level 2 Luck
10= Cursed & Jinxed -or- (roll 1D6) 1-5= Lesser Wish, 6= Wish

b) Hybrid Animals 
Roll 2D6 (in all cases choose the most noteworthy feature(s) of the creature(s) in question)
2= Combination of 1D6+2 creatures
3-4= Combination of 1D6 (min 2) creatures
5-6= Combination of 1D6-2 (min 2) creatures
7= Combination of 2 creatures
8-9= Combination of 1D6-1 (min 2) creatures
10-11= Combination of 1D6+1 creatures
12= Combination of 2D6 creatures

c) Talking Animals
Roll 2D6
2= Animal only speaks false prophecy, otherwise it has only animal intellect.
3-4= Animal can speak and is 50% smarter than a human. (Also roll on Magical Animals table)
5-6= Animal can speak and is 50% smarter than an average human.
7= Animal can speak and has an intellect equal to the average of that animal and a human.
8-9= Animal can speak and is as intelligent as a human.
10-11= Animal can speak and is as intelligent as a human. (Also roll on Magical Animals table)
12= Animal only speaks prophecy, otherwise it has only animal intellect.

d) Animals with Many Lives 
Roll 2D6 (roll 3D6-3 (0 = 3D6 hours) for the number of days it takes to come back to life)
2-5= 2D lives (if odd roll = can be permanently killed; roll on invulnerability table)
6-8= 1D lives (if odd roll = can be permanently killed; roll on invulnerability table)
9-11= 2D lives (if odd roll = can be permanently killed; roll on invulnerability table)
12= 3D lives (if odd roll = can be permanently killed; roll on invulnerability table)

e) Unnatural Powers of Flight
Roll 2D6
2= No wings, flies at 5D6 yards per second
3-4= No wings, flies at 3D6 yards per second
5-6= Wings, flies at 2D6+2 yards per second
7= Wings, flies at 2D6 yards per second (this can result in some verrrry slooooow fliers)
8-9= Wings, flies at 2D6+2 yards per second
10= Wings, flies at 3D6+1 yards per second
11= Wings, flies at 4D6 yards per second
12= Wings, flies at 5D6 yards per second

f) Animals with Multiple or Unusual Heads 
Roll 2D6
2-3= 2D+1 heads, not coordinated
4-5= 1D+1 heads, not coordinated
6-8= 2 headed, (roll 1D; 1-3= not coordinated, 4-6= full coordination)
9-10= 1D+1 heads, full coordination
11-12= 2D+1 heads, full coordination

Roll 2D6 (types of heads)
2-4= 1D+1 different animals heads
5-6= 1D-2 (min 2) different animals heads
7= Same as original head, (roll 1D 1-3= no special attack, 4-6= special attack)
8-9= 1D-2 (min 2) different heads, special attack
10-12= 1D+1 different heads, special attack

g) Animals with Multiple or Unusual Limbs
Roll 3D6 (all manipulatory limbs roll 1D6 1-4 Fully coordinated, 5-6 uncoordinated)
3= Roll twice and combine results
4= Manipulatory limbs are 3 times as long as normal -or- normal move x 3
5= Gain 1D6-2 (min 1) striking limbs (Roll 1D6 1-2= dagger, 3-4= mace, 5-6= shortsword)
6= Manipulatory limbs are tentacular and twice as long -or- normal move doubled
7= Manipulatory limbs are twice as long as normal -or- normal move x 1.5
8= A 1D6-2 (min 1) extra pair of limbs (Roll 1D6 1-4= locomotive, 5-6= manipulatory)
9= A 1D6-3 (min 1) extra pair of limbs (Roll 1D6 1-4= locomotive, 5-6= manipulatory)
10= An extra pair of limbs (Roll 1D6 1-4= locomotive, 5-6= manipulatory)
11= A 1D6-3 (min 1) extra pair of limbs (Roll 1D6 1-4= locomotive, 5-6= manipulatory)
12= A 1D6 extra pair of limbs (Roll 1D6 1-4= locomotive, 5-6= manipulatory)
13= Manipulatory limbs are twice as long as normal -or- normal move x 1.5
14= Prehensile tail (tail length = body height/length) 
15= Tail gains snake's head (tail length = 1/2 body height/length) -or- as # 14
16= Gain eyes on limbs (Roll 1D6 1-4= locomotive, 5-6= manipulatory)
17= Gain a single manipulatory limb (Roll 1D6 1-3= from upper torso, 4-6= from tail)
18= Roll three times and combine results

h) Giant Animals 
Roll 2D6 (each level of scale is a multiple of normal size)
2= Scale + 6
3= Scale + 5
4= Scale + 4
5= Scale + 3
6= Scale + 2
7= Scale + 1
8= Scale + 1D-3 (min 1)
9= Scale + 1D-2 (min 1)
10= Scale + 1D-1 (min 1)
11= Scale + 1D+2
12= Scale +2D

i) Unnaturally Venomous Animals 
Roll 2D6 (Damage is given as % of average human hit points, this should be average damage)
2-4= Creature has poisonous spines (damage 75%)
5-11= Bite of creature is poisonous (damage 100%)
12= Flesh, blood or certain organ of creature is highly poisonous (damage 200%)

Roll 2D6
2= Poison type = Magical poison (shrinking, madness, fear, etc)
3-5= Poison type =Paralyzing venom
6-8= Poison type = Rattlesnake type venom (fairly immediate damaging effects)
9-11= Poison type = Slow acting poison
12= Poison type = Nerve gas type effects

j) Unnaturally Carnivorous Animals 
Roll 2D6
2= As 12, and is immune from any "normal" animal control spells.
3-5= Normal teeth and feet replaced by carnivorous teeth and claws.
6-8= Normal teeth replaced by sharp, carnivore type teeth.
9-11= As 3-5, but mouth is larger than normal allowing a much larger bite radius.
12= As 9-11, and also goes berserk at the scent of blood.

k) Animals with Full or Partial Invulnerability 
Roll 3D6
3-6= Certain Spot on Body (Roll on a Hit Location Table)
7-10= Certain Weapons or Magic (Roll 1D6 1-4= weapon, 5-6= magic)

Roll 2D6
2= Very specific. (Ex: a unique greatsword, a spell designed to kill this beast)
3= Specific make and type. (Ex: steel greatswords, fireball)
4= Specific type or college. (Ex: greatswords, damaging fire magic)
5-6= Certain class or type of spell. (Ex: swords, damaging elemental spells)
7= A broad category. (Ex: cutting weapons, any damaging spell)
8-9= Certain class or type of spell. (Ex: swords, elemental spells)
10= Specific type. (Ex: greatswords, fire magic)
11= Specific make and type. (Ex: steel greatswords, fireball)
12= Very specific. (Ex: a unique greatsword, a spell designed to kill this beast)

11-13= Certain People

Roll 2D6
2= A specific individual (usually fated to battle creature)
3= A member of a small group of people (Ex: seventh sons of a seventh son)
4= A member of a medium group of people (Ex: mercenaries, red-heads)
5-6= A member of a large class of people (Ex: soldiers, brunettes)
7= A member of a certain gender (roll 1D6 1-3= male, 4-6= female)
8-9= A member of a large class of people (Ex: a particular race or religion)
10= A member of a medium group of people (Ex: virgin females, a specific nationality)
11= A member of a small group of people (Ex: albinos, epilectics)
12= A specific individual (usually fated to battle creature)

14-17= Certain Situations

Roll 2D6
2= Extremely limited time frame (Ex: during an eclipse)
3= Very limited time frame (Ex: only during one minute of each day, on the equinoxes)
4= Limited time frame (Ex: the hour from midnight til one, one day per month)
5-6= Moderate time frame (Ex: while it is asleep, while raining)
7= Fifty percent or so of the time (Ex: during daylight)
8-9= Specific situation (Ex: while singing, dress all in white)
10= Dangerous situation (Ex: two people holding hands)
11= Very dangerous or difficult situation (Ex: while blindfolded, in running water)
12= Rare situation (Ex: naked in rain and carrying the skull of a relative)

18= Total Invulnerability

Roll 2D6
2= No physical damage taken at all (choking, drowning will still work)
3-5= All physical damage divided by 2D6 before armor applied
6-8= All physical damage divided by 1D6 (min 2) before armor applied 
9-11= All physical damage divided by 3D6 before armor is applied
12= Creature cannot be harmed by any physical means (no fire, drowning, etc)

l) Animals that are Part Human 
Roll 2D6
2= Centaur-like arrangement, full human intellect.
3-4= Human body with animal head, normal human intellect, few animal traits.
5-6= Human body with animal head, some reasoning power and will have many traits of the animal form (average of animal and human intellect).
7= Human body with animal head, no reasoning power beyond the norm for that animal.
8-9=Animal body with human head, some reasoning power and will have many traits of the animal (average of animal and human intellect).
10-11= Animal body with human head, no reasoning power beyond the norm for that animal.
12= Normal animal body with normal human intellect.

m) Animals with Magical Powers 
Roll 3D6 
3= Has 1D6+2 combat spells that can be used 3D6 times with an hour to "recharge" each use. A minor permanent spell may also be chosen.
4= Has 1D6-1 (min1) combat spells that can be used 1D6+2 times with an hour to "recharge" each use. A minor permanent spell may also be chosen.
5= Has 1D6-3 (min1) combat spells that can be used 1D6 times with an hour to "recharge" each use. A minor permanent spell may also be chosen.
6= Has 1D6+2 minor combat spells that can be used 2D6+2 times with an hour to "recharge" each use. A very minor permanent spell may also be chosen.
7= Has 1D6 minor combat spells that can be used 2D6 times with an hour to "recharge" each use. A very minor permanent spell may also be chosen.
8= Has 1D6-2 (min1) minor combat spells that can be used 1D6+2 times with an hour to "recharge" each use. A very minor permanent spell may also be chosen.
9= Has 1D6-4 (min1) minor combat spells that can be used 1D6 times with an hour to "recharge" each use. A very minor permanent spell may also be chosen.
10= Has one fairly minor spell that can be used 1D6 times with an hour to "recharge" each use.
11= Has 1D6-4 (min1) minor non-combat spells that can be used 1D6 times with an hour to "recharge" each use. A very minor permanent spell may also be chosen.
12= Has 1D6-2 (min1) minor non-combat spells that can be used 1D6+2 times with an hour to "recharge" each use. A very minor permanent spell may also be chosen.
13= Has 1D6 minor non-combat spells that can be used 2D6 times with an hour to "recharge" each use. A very minor permanent spell may also be chosen.
14= Has 1D6+2 minor non-combat spells that can be used 2D6+2 times with an hour to "recharge" each use. A very minor permanent spell may also be chosen.
15= Has 1D6-3 (min1) non-combat spells that can be used 1D6 times with an hour to "recharge" each use. A minor permanent spell may also be chosen.
16= Has 1D6-1 (min1) non-combat spells that can be used 1D6+2 times with an hour to "recharge" each use. A minor permanent spell may also be chosen.
17= Has 1D6+1 non-combat spells that can be used 2D6 times with an hour to "recharge" each use. A minor permanent spell may also be chosen.
18= Has 1D6-3 (min 1) powerful non-combat spells that it can cast an unlimited number of times

n) Animals that Transform 
Roll 3D6
3= Animal cannot stay in any one form and changes to whatever is beneficial to it at the time.
4= Animal can change into some beneficial animal for humans that please it
5= Animal can change into smaller, fleeter animal for purposes of escape
6= Animal can change into a much larger animal (at least 10 times bigger)
7= Animal can change into a larger, predatory animal
8= Animal can change into human form and gain some human intellect (avg of intellects).
9= Animal can change into human form and has human intellect all the time.
10= Animal can change into human form and gain some human intellect (avg of intellects).
11= Animal can change into human form retaining only animal intellect.
12= Can change size. Roll 1D6 1-2= (+1D6 x 100%) 3-4= (-3D6+2 x 5% [max -99%]) 5-6= Both
13= Changes into rocks at either sunup or sundown. They don't look like animal while stone.
14= Can change size. Roll 1D6 1-3= (+2D6 x 100%) 4= (-3D6+4 x 5% [max -99%]) 5-6= Both.
15= Can change into a tree or shrub.
16= Can change size. Roll 1D6 1-3= (+3D6 x 100%) 4= (-2D6+8 x 5% [max -99%]) 5-6= Both.
17= Can change into rocks at any time.
18= Can change into gaseous form.

o) Animals with Devastating Breath or Looks
Roll 2D6 (Damage is given as % of average human hit points, this should be average damage)
2= Gaze attack (turns target to stone, bronze, dust, etc)
3= Gaze attack (roll for poison type, damage 50%)
4= Breath attack (damage 100% times weight/100)
5= Breath attack (damage 100% times weight/250)
6= Breath attack (damage 100% times weight/500)
7= Breath attack (damage 100% times weight/1000)
8= Breath attack (damage 100% times weight/500)
9= Breath attack (damage 100% times weight/250)
10= Breath attack (damage 100% times weight/100)
11= Gaze attack (damage 50%)
12= Gaze attack (damage 100%)

Roll 2D6
2= Breath Type = Acid with corrosive gas cloud (25% acid's damage if breathed, 10% acid's damage from contact with gas cloud)
3= Breath Type = Acid
4= Breath Type = Liquid contact poison, 200% effectiveness (roll for type)
5= Breath Type = Poison gas cloud, 150% effectiveness (roll for type)
6= Breath Type = Poison gas cloud (roll for type)
7= Breath Type = Fire
8= Breath Type = Fire with 150% effectiveness
9= Breath Type = Fire with gaseous poison cloud (roll for type)
10= Breath Type = Fire with 200% effectiveness
11= Breath Type = Napalm type burning fluid, with 150% effectiveness
12= Breath Type = Napalm type burning fluid, 200% effectiveness, and poison gas cloud

Roll 2D6
2= Poison type = Magical poison (shrinking, madness, fear, etc)
3-5= Poison type =Paralyzing venom
6-8= Poison type = Rattlesnake type venom (fairly immediate damaging effects)
9-11= Poison type = Slow acting poison
12= Poison type = Nerve gas type effects

p) Animals that are Part Mineral 
Roll 2D6 (GM should modify physical attributes (speed, DEX, etc) based on relative encumbrance of the results. (Ex: A stone animal might be slower than normal) 
2= Creature is made of metal (armor & hit points +20D6 x 10%) also add # 11
3= Creature is made of metal (armor & hit points +10D6 x 10%) also [Roll 1D6 1-4= add # 11 5-6= nothing extra]
4= Creature is made of stone (armor & hit points +6D6 x 10%) also [Roll 1D6 1= add # 11 2-6= nothing extra]
5= Hide made of stone or non-precious metal (armor value +6D6 x 10%)
6= Hide made of stone or non-precious metal (armor value +4D6 x 10%)
7= Hide made of stone or non-precious metal (armor value +2D6 x 10%) 
8= Hide made of stone or non-precious metal (armor value +3D6 x 10%)
9= Hide made of stone or non-precious metal (armor value +5D6 x 10%)
10= Hide made of semi-precious gems or precious metal (armor value +2D6 x 10%)
11= Creature has organ made from a large precious gem. (50% chance gem is magical)
12= Creature is made of a precious metal (armor & hit points +3D6 x 10%)


Monstrous Plants
Roll 2D6
2= Plant has magical fruit (roll on magical fruit table)
3= Plant can speak (roll on talking plant table)
4= As in # 7, but plant is fully mobile.
5-6= As in # 7, but only in self defense.
7= Otherwise sessile plant can move (branches, vines, etc) to capture fertilizer on the hoof.
8-9= As in # 7, but plant is actively carnivorous and has some way to eat it's prey.
10= As in # 8-9, but plant is fully mobile.
11= Plant has active poisonous attack (roll on poisonous plant attack table)
12= As in # 8-9 and # 11.

Roll 2D6 (Magical Fruit Table)
2= Fruit has very powerful beneficial effect (Wish, Resurrect, etc)
3= Fruit has multiple beneficial effects (choose 1D3+1 interesting, complimentary spells)
4= Fruit has beneficial effect (choose an interesting spell of moderate power)
5= Fruit has curative power (choose a healing type spell)
6= Fruit has some mild curative power (choose a weak healing type spell)
7= Fruit is unnaturally tasty and filling (one fruit acts as a whole meal)
8= Fruit has some mild unpleasant effect (choose a mild deleterious spell)
9= Fruit has some beneficial effect followed by a deleterious effect (choose appropriate spells that complement each other {Ex: Increased strength followed by berserker}).
10= Fruit has some unpleasant and dangerous effect (choose a deleterious spell)
11= Fruit is incredibly tasty, but devastatingly poisonous (long term 500% damage)
12= Fruit has very powerful deleterious effect (choose a powerful evil spell)

Roll 2D6 (Talking Plant Table)
2= Plant only speaks prophecy.
3-4= Plant can speak and is 50% smarter than a human, and has a beneficial spell. 
5-6= Plant can speak and is as intelligent as a human.
7= Plant can speak and has an intellect equal to 1/2 the average human.
8-9= Plant can speak and is as intelligent as a human.
10-11= Plant can speak and is 50% smarter than an average human, and has an evil spell.
12= Plant only speaks false prophecy. 

Roll 2D6 (Poisonous Plant Attack Table) (Damage given in % of normal human hit points)
2= Fruit explodes and emits poison gas (damage 20%)
3-4= Plant can squirt contact poison (skill = average) (damage 30%)
5-6= Plant can emit a cloud of poison gas (damage 50%)
7= Plant can emit a cloud of poison gas (damage 25%)
8-9= Plant can emit a cloud of poison gas (damage 100%)
10-11= Plant can fire envenomed dart/thorns (skill = clumsy) (damage 20% each)
12= Plant can fire envenomed dart/thorns (skill = average) (damage 50% each)

 

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