Large dragon, unaligned

Armor Class 13 (natural armor)
Hit Points 110 (13d10 + 39)
Speed 20 ft., fly 80 ft.

STR	DEX	CON	INT	WIS	CHA
19 (+4)	10 (+0)	16 (+3)	5 (-3)	12 (+1)	6 (-2)

Saving Throws 
Skills Perception +4
Damage Resistances 
Damage Immunities 
Condition Immunities 
Senses darkvision 60 ft., passive Perception 14
Languages --
Challenge 6 (2300 XP)

Actions

Multiattack. The wyvern makes two attacks: one with its bite and one with its stinger. While flying, it can use its claws in place of one other attack.

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one creature. Hit: 11 (2d6 + 4) piercing damage.

Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage.

Stinger. Melee Weapon Attack: +7 to hit, reach 10 ft., one creature. Hit: 11 (2d6 + 4) piercing damage. The target must make a DC 15 Constitution saving throw, taking 24 (7d6) poison damage on a failed save, or half as much damage on a successful one.

Large monstrosity, neutral evil

Armor Class 13 (natural armor)
Hit Points 26 (4d10 + 4)
Speed 50 ft.

STR	DEX	CON	INT	WIS	CHA
16 (+3)	13 (+1)	13 (+1)	7 (-2)	11 (+0)	8 (-1)

Saving Throws 
Skills Perception +4
Damage Resistances 
Damage Immunities 
Condition Immunities 
Senses darkvision 60 ft., passive Perception 14
Languages Goblin, Worg
Challenge 44928 (100 XP)

Keen Hearing and Smell. The worg has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) piercing damage. If the target is a creature, it must succeed on a DC 13 Strength saving throw or be knocked prone. A worg is an evil predator that delights in hunting and devouring creatures weaker than itself. Cunning and malevolent, worgs roam across the remote wilderness or are raised by goblins and hobgoblins. Those creatures use worgs as mounts, but a worg will turn on its rider if it feels mistreated or malnourished. Worgs speak in their own language and Goblin, and a few learn to speak Common as well.

Medium swarm of Tiny beasts, unaligned

Armor Class 10
Hit Points 24 (7d8 - 7)
Speed 30 ft.

STR	DEX	CON	INT	WIS	CHA
9 (-1)	11 (+0)	9 (-1)	2 (-4)	10 (+0)	3 (-4)

Saving Throws 
Skills 
Damage Resistances bludgeoning, piercing, slashing
Damage Immunities 
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses darkvision 30 ft., passive Perception 10
Languages --
Challenge 44930 (50 XP)

Keen Smell. The swarm has advantage on Wisdom (Perception) checks that rely on smell.

Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny rat. The swarm can’t regain hit points or gain temporary hit points.

Actions

Bites. Melee Weapon Attack: +2 to hit, reach 0 ft., one target in the swarm’s space. Hit: 7 (2d6) piercing damage, or 3 (1d6) piercing damage if the swarm has half of its hit points or fewer.

Medium swarm of Tiny beasts, unaligned

Armor Class 12
Hit Points 24 (7d8 - 7)
Speed 10 ft., fly 50 ft.

STR	DEX	CON	INT	WIS	CHA
6 (-2)	14 (+2)	8 (-1)	3 (-4)	12 (+1)	6 (-2)

Saving Throws 
Skills Perception +5
Damage Resistances bludgeoning, piercing, slashing
Damage Immunities 
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses passive Perception 15
Languages --
Challenge 44930 (50 XP)

Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny raven. The swarm can’t regain hit points or gain temporary hit points.

Actions

Beaks. Melee Weapon Attack: +4 to hit, reach 5 ft., one target in the swarm’s space. Hit: 7 (2d6) piercing damage, or 3 (1d6) piercing damage if the swarm has half of its hit points or fewer.

Medium swarm of Tiny beasts, unaligned

Armor Class 12 (natural armor)
Hit Points 22 (5d8)
Speed 20 ft., climb 20 ft.

STR	DEX	CON	INT	WIS	CHA
3 (-4)	13 (+1)	10 (+0)	1 (-5)	7 (-2)	1 (-5)

Saving Throws 
Skills 
Damage Resistances bludgeoning, piercing, slashing
Damage Immunities 
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses blindsight 10 ft., passive Perception 8
Languages --
Challenge 44928 (100 XP)

Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny insect. The swarm can’t regain hit points or gain temporary hit points.

Actions

Bites. Melee Weapon Attack: +3 to hit, reach 0 ft., one target in the swarm’s space. Hit: 10 (4d4) piercing damage, or 5 (2d4) piercing damage if the swarm has half of its hit points or fewer.

Variant: Insect Swarms

Different kinds of insects can gather in swarms, and each swarm has the special characteristics described below.

Swarm of Beetles. A swarm of beetles gains a burrowing speed of 5 feet.

Swarm of Centipedes. A creature reduced to 0 hit points by a swarm of centipedes is stable but poisoned for 1 hour, even after regaining hit points, and paralyzed while poisoned in this way.

Swarm of Spiders. A swarm of spiders has the following additional traits.
Spider Climb. The swarm can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Web Sense. While in contact with a web, the swarm knows the exact location of any other creature in contact with the same web. Web Walker. The swarm ignores movement restrictions caused by webbing.

Swarm of Wasps. A swarm of wasps has a walking speed of 5 feet, a flying speed of 30 feet, and no climbing speed.

Large ooze, unaligned

Armor Class 8
Hit Points 45 (6d10 + 12)
Speed 10 ft., climb 10 ft.

STR	DEX	CON	INT	WIS	CHA
15 (+2)	6 (-2)	14 (+2)	2 (-4)	6 (-2)	1 (-5)

Saving Throws 
Skills 
Damage Resistances acid
Damage Immunities lightning, slashing
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, prone
Senses blindsight 60 ft. (blind beyond this radius), passive Perception 8
Languages --
Challenge 2 (450 XP)

Amorphous. The jelly can move through a space as narrow as 1 inch wide without squeezing.

Spider Climb. The jelly can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Actions

Pseudopod. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 9 (2d6 + 2) bludgeoning damage plus 3 (1d6) acid damage.

Reactions

Split. When a jelly that is Medium or larger is subjected to lightning or slashing damage, it splits into two new jellies if it has at least 10 hit points. Each new jelly has hit points equal to half the original jelly’s, rounded down. New jellies are one size smaller than the original jelly.

Medium swarm of Tiny beasts, unaligned

Armor Class 12
Hit Points 22 (5d8)
Speed 0 ft., fly 30 ft.

STR	DEX	CON	INT	WIS	CHA
5 (-3)	15 (+2)	10 (+0)	2 (-4)	12 (+1)	4 (-3)

Saving Throws 
Skills 
Damage Resistances bludgeoning, piercing, slashing
Damage Immunities 
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses blindsight 60 ft., passive Perception 11
Languages --
Challenge 44930 (50 XP)

Echolocation. The swarm can’t use its blindsight while deafened.

Keen Hearing. The swarm has advantage on Wisdom (Perception) checks that rely on hearing.

Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny bat. The swarm can’t regain hit points or gain temporary hit points.

Actions

Bites. Melee Weapon Attack: +4 to hit, reach 0 ft., one creature in the swarm’s space. Hit: 5 (2d4) piercing damage, or 2 (1d4) piercing damage if the swarm has half of its hit points or fewer.

Medium swarm of Tiny beasts, unaligned

Armor Class 13
Hit Points 28 (8d8 - 8)
Speed 0 ft., swim 40 ft.

STR	DEX	CON	INT	WIS	CHA
13 (+1)	16 (+3)	9 (-1)	1 (-5)	7 (-2)	2 (-4)

Saving Throws 
Skills 
Damage Resistances bludgeoning, piercing, slashing
Damage Immunities 
Condition Immunities charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses darkvision 60 ft., passive Perception 8
Languages --
Challenge 1 (200 XP)

Blood Frenzy. The swarm has advantage on melee attack rolls against any creature that doesn’t have all its hit points.

Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny quipper. The swarm can’t regain hit points or gain temporary hit points.

Water Breathing. The swarm can breathe only underwater.

Actions

Bites. Melee Weapon Attack: +5 to hit, reach 0 ft., one creature in the swarm’s space. Hit: 14 (4d6) piercing damage, or 7 (2d6) piercing damage if the swarm has half of its hit points or fewer.

Large undead, neutral evil

Armor Class 8
Hit Points 85 (9d10 + 36)
Speed 30 ft.

STR	DEX	CON	INT	WIS	CHA
19 (+4)	6 (-2)	18 (+4)	3 (-4)	6 (-2)	5 (-3)

Saving Throws Wis +0
Skills 
Damage Resistances 
Damage Immunities poison
Condition Immunities poisoned
Senses darkvision 60 ft., passive Perception 8
Languages understands Common and Giant but can't speak
Challenge 2 (450 XP)

Undead Fortitude. If damage reduces the zombie to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombie drops to 1 hit point instead.

Actions

Morningstar. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.

Medium ooze, unaligned

Armor Class 8
Hit Points 22 (3d8 + 9)
Speed 10 ft., climb 10 ft.

STR	DEX	CON	INT	WIS	CHA
12 (+1)	6 (-2)	16 (+3)	1 (-5)	6 (-2)	2 (-4)

Saving Throws 
Skills Stealth +2
Damage Resistances acid, cold, fire
Damage Immunities 
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, prone
Senses blindsight 60 ft. (blind beyond this radius), passive Perception 8
Languages --
Challenge 44928 (100 XP)

Amorphous. The ooze can move through a space as narrow as 1 inch wide without squeezing.

Corrode Metal. Any nonmagical weapon made of metal that hits the ooze corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed. Nonmagical ammunition made of metal that hits the ooze is destroyed after dealing damage. The ooze can eat through 2-inch-thick, nonmagical metal in 1 round.

False Appearance. While the ooze remains motionless, it is indistinguishable from an oily pool or wet rock.

Actions

Pseudopod. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage plus 7 (2d6) acid damage, and if the target is wearing nonmagical metal armor, its armor is partly corroded and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.