The Dungeon Master’s Handbook: Mutating Your Minions

I like using minions and low CR monsters to help fill out important combat encounters or just to pad out an adventure. It’s easy for giant animals and skeletons to get stale quickly. So I made a d20 list of some mutant powers you can give to almost any monster to make a unique and memorable encounter. I even included some harvesting tips in case your players want to craft their own potions or sell them to a merchant.

Here are some quick monster stat blocks to use with the mutations.

  1. Bandit. AC 11. HP 11 (3d6). Sword/Crossbow (M/R), +4 to hit, 4 (1d8) piercing damage.
  2. Blight. AC 12. HP 11 (3d6). Claws/Needles (M/R), +4 to hit, 4 (1d8) piercing damage.
  3. Giant Rat. AC 12. HP 7 (2d6). Bite (M), +4 to hit, 4 (1d8) piercing damage. Pack Tactics.
  4. Goblin. AC 15. HP 7 (2d6). Sword/Bow (M/R), +4 to hit, 4 (1d8) piercing damage. Nimble Escape.
  5. Grimlock. AC 11. HP 11 (3d6). Spiked Club (M), +4 to hit, 4 (1d8) bludgeoning and 3 (1d6) piercing damage.
  6. Kobold. AC 12. HP 7 (2d6). Dagger/Sling (M/R), +4 to hit, 4 (1d8) bludgeoning or piercing damage. Pack Tactics.
  7. Mephit. AC 12. HP 17 (5d6). Claws (M), +4 to hit, 4 (1d8) slashing damage. Death Burst.
  8. Sahuagin. AC 12. HP 21 (6d6). Bite/Claws/Spear (M/M/R), +4 to hit, 4 (1d8) piercing/slashing/piercing damage. Blood Frenzy.
  9. Skeleton. AC 13. HP 14 (4d6). Sword/Bow (M/R), +4 to hit, 4 (1d8) piercing damage.
  10. Zombie. AC 8. HP 21 (6d6). Slam (M), +4 to hit, 4 (1d8) bludgeoning damage. Undead Fortitude.

Consider giving the Mephit and Grimlock two mutations. A boss or mini-boss monster should have two mutations and two attacks. To make these Minions tougher just increase the number of die for HP or damage. You can also increase the to hit bonus’ by one every 3 character levels. 

d20 Mutations

The following mutations are intended to be added to a statblock as extra options for its normal attacks. They are designed to imitate common wizard spells, damage types, and creature types. Roll a d8 for an easy ability, a d12 for intermediate abilities, and a d20 for the most powerful options. Or choose your own.

  1. Fire. Hurls a ball of fire at a creature within range. 
    • Fire Bolt (Range 30 ft.), +4 to hit, 5 (1d10) fire damage.
  2. Cold. Numbing frost forms along the ground in a straight line.
    • Frost Strike (Line 15 ft.), DC 12 CON save vs. half damage, 5 (1d10) cold damage.
  3. Lightning. A burst of lightning sweeps out.
    • Lightning Burst (Self, 5 ft. radius), DC 12 CON save vs half damage, 4 (1d8) lightning damage.
  4. Acid. Spits a bubble of acid at a creature in range.
    • Acid Spit (Range 30 ft.), +4 to hit, 5 (1d10) acid damage.
  5. Dragon Breath. The creature exhales in a 15 ft cone. 1d4: acid, lightning, fire, cold.
    • Breath Weapon (15 ft. cone), DC 12 DEX save vs half damage, 5 (1d10) fire damage.
  6. Psychic. A psychic swipe takes the damage amount off of the next saving throw.
    • Psychic Swipe (Melee), +4 to hit, 4 (1d8) psychic damage.
    • On a hit, the damage amount is subtracted from the target’s next attack, ability check, or saving throw.
  7. Radiant. Mystical dim light glitters around a damaged target.
    • Radiant Swipe (Melee), +4 to hit, 4 (1d8) radiant damage.
    • On a hit, the next attack on the target has advantage.
  8. Necrotic. Each attack heals the creature for the amount of damage dealt.
    • Necrotic Swipe (Melee), +4 to hit, 4 (1d8) necrotic damage.
    • The creature regains a number of hit points equal to the necrotic damage.
  9. Water. Shoots a shard of ice at a creature in range. 
    • Ice Bolt (Range 20 ft.), +4 to hit, 4 (1d8) cold damage.
    • On a hit, the target makes a DC 12 CON save vs. reducing speed by 10 ft for 1 round.
  10. Roll twice and combine the two.
  11. Elemental. Shards of elemental magic have been bound to the giant creature.
    • Elemental Bite (Melee), +4 to hit, 4 (1d8) force damage.
    • Elemental Shield. The giant creature has resistance to bludgeoning, piercing, and slashing from non-magical attacks.
  12. Construct. An assortment of creature parts stitched and bolted together.
    • Slam (Melee), +4 to hit, 4 (1d8) bludgeoning damage.
    • Magic Resistance. The giant creature has advantage on saving throws against spells and other magical effects.
  13. Ooze. The creature resembles a heaving mound of sticky black sludge.
    • Acidic Bite (Melee), +4 to hit, 4 (1d8) acid damage.
    • Corrosive Form: Non Magical weapons that hit the creature take -1 penalty to damage rolls. The weapon is destroyed if the penalty drops to -5.
  14. Undead. Necromantic magic animates the remains of a dead creature.
    • Slam (Melee), +4 to hit, 4 (1d8) bludgeoning damage.
    • Undead Fortitude: If an attack reduces the creature to 0 HP the zombie drops to 1 HP instead, one time.
  15. Thunder. A wave of thunderous force sweeps out.
    • Thunder wave: All creatures within 5 ft. of the creature make a DC 12 STR save vs 10 ft pushback.
  16. Fey. A fey mystique surrounds the giant creature.
    • Fey Presence: One creature the creature can see within 30 ft make a DC 12 WIS save vs being frightened or charmed for 1 min.
  17. Air. A faint but constant breeze follows the creature.
    • Gust Of Wind: A whirlwind erupts from the creature and each creature in a 5 ft. radius makes a DC 12 STR save vs being pushed back 10 ft.
  18. Earth. The creature’s fur is matted with dirt, stone, and gems.
    • Slam (Melee), +4 to hit, 4 (1d8) bludgeoning damage.
    • Tremor: The creature stomps trembling the ground, and each creature in a 5 ft radius makes a DC 12 DEX save vs being knocked prone.
  19. Demonic. Spawned in the Abyss, formed of filth and carnage.
    • Devil’s Sight: The creature can cast darkness centered on itself and can see through magical darkness.
  20. Magic Missiles. The creature carries a wand of magic missiles.
    • Can cast Magic Missile at 2nd level 3 times per day.


PCs can make a DC 15 Nature or Medicine check to harvest one of the glands in the monster that produces the mutation. DC 20 enables the harvest of two glands of the same mutation or one each of two mutations.  The minimum time is 1 hour for getting ready, harvesting, and cleaning up.

Quick and Easy Adventure Builder

Use this table to build an adventure. Roll for the type of quest, the item involved, what magic the item has, and where the adventure takes place. Roll 3 times on the monster list above using a d8, a d12, and a d20. The first two are minions with one mutation and the third is the big boss with two mutations. Don’t be afraid to mix up mutations within a group of monsters.

Roll a d10 for each or choose your own.

1Find an itemNecklaceShatterTemple, map
2Kill a VillainBroochFlyTomb, map
3Clear out monstersBraceletLightning BoltCove, map
4Protect a monumentCircletGuiding BoltVault, map
5Steal an itemRingSpiritual WeaponSanctum, map
6Retrieve an itemCandleHasteShip, map
7Disable an artifactBowlBurning HandsKeep, map
8Convince an NPCBoneDaylightTower, map
9Put a monster to sleepGemstoneShieldMines, map
10Bury an artifactBellScorching RayCastle, map

d4 NPC Quest Givers

  1. A humorous dwarf clerk with a half-shaved head named Osborne Anvilcloud
  2. An elitist dragonborn apothecary with a feathered earring named Tansa Hollyfang
  3. A wide-eyed human farmer with multicolored eyes named Vesta Redspur
  4. A selfless halfling guide with a missing eye named Wynfreed Lightblade

Example Adventure

Quest: retrieve an item (6)

Item: bracelet (3)

Spell: spiritual weapon (5)

Location: mines (9)

Quest Giver: Vesta Redspur (3)

Minion 1: giant rats that spit acid (3, 4)

Minion 2: mephit that shoots a numbing frost (7, 2)

Boss: bandit that shoots ice bolts and can control the wind (1, 9, 17)

The PCs are hired by the farmer Vesta Redspur to retrieve a family heirloom, the Celestial’s Embrace. The gilded bracelet contains stones that match the family’s shared genetic multicolored eyes and it is known to protect its bearer from danger. The bandit Frostbane has made off with it to their lair in an abandoned mine located outside of town. Vesta is planning on using it for their daughters’ dowry later in the year and will pay up to 50 gp per character upon delivery. The PCs can talk to the townspeople about Frostbane and his followers or try to find a map for the old mine. 

On their way to the mine, the PCs must overcome not only difficult terrain and environmental hazards but must confront giant acid-spitting rats angered by them crossing into their territory. Once in the mine they find winding passages and collapsed tunnels. The party must navigate the traps and Mephit minions that Frostbane has set to guard his lair. Finding Frostbane deep in the mines the PCs must contend with his archery skills and elemental magic.

Once the PCs recover the bracelet they can bring it back to Vesta for their reward and a well-deserved rest.

Difficult Terrain. dense forest. DC 11 stealth or nature check to not be ambushed by giant rats.

Encounter 1. one or two giant acid rats per PC

Giant Rat. AC 12. HP 7 (2d6). Bite (M), +4 to hit, 4 (1d8) piercing damage. Acid Spit (Range 30 ft.), +4 to hit, 5 (1d10) acid damage. Pack Tactics.

Trap. fog cloud vent. DC 12 perception/investigation check to notice the trigger. DC 12 dex check to disable it. 20 ft radius sphere of heavily obscured fog.

Encounter 2. one or two frost mephits per PC

Mephit. AC 12. HP 17 (5d6). Claws (M), +4 to hit, 4 (1d8) slashing damage. Frost Strike (Line 15 ft.), DC 12 CON save vs. half damage, 4 (1d8) cold damage. Death Burst.

Hazard. brown mold. Frostbane’s frigid magic has allowed a patch of brown mold to thrive.

Encounter 3. frostbane the bandit and 1 mephit per PC

Frostbane. AC 12. HP 21 (6d6). Two Attacks. Sword/Crossbow (M/R), +4 to hit, 4 (1d8) piercing damage. Ice Bolt (R 20 ft.), +4 to hit, 4 (1d8) cold damage. On a hit, the target makes a DC 12 CON save vs. reducing speed by 10 ft for 1 round. Gust Of Wind. A whirlwind erupts from the creature and each creature in a 5 ft. radius makes a DC 12 STR save vs being pushed back 10 ft.

As always, good luck with your next session, I believe in you! See you in the future.

The Adventure Builder and Quest Giver tables are derived from content made by Sly Flourish in The Lazy GM’s Resource Document, which is licensed under CC BY 4.0

This work includes material taken from the System Reference Document 5.1 (“SRD 5.1”) by Wizards of the Coast LLC and available here. The SRD 5.1 is licensed under the Creative Commons Attribution 4.0 International License available here.

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