5E: Monstrous Arthropods for Fifth Edition

[Casimir Liber]

Looks good - two "incredible/-y" near each other - I'd substitute another word maybe

 

[Cleon]

Looks good - two "incredible/-y" near each other - I'd substitute another word maybe

Dang it, you're right.

It would be in the only paragraph I didn't triple check.

Will change the second one to "extremely wide".

 

[Cleon]

Incidentally, I briefly toyed with the idea of mentioning faerzress in the bit about Underdark magical radiation, but decided it was inappropriate to use a Forgotten Realms specific term.

Although arguable "Underdark" is FR specific, but I think that's got wide enough use in D&D now it can squeak through!

 

[Cleon]

My first attempt used the CHA-based save DC standard to enchantment type effects, but that was only DC 9 which seemed way too low so I made it DEX-based on the basis that it's a motion-based ability. Thought about a WIS-based DC 12, but that didn't make much sense to me, and having the CHA-based DC 9 with disadvantage if being viewed with darkvision, but to do that I'd have to make the phrasing more complicated and it didn't seem worth it.

Further on that, I'm still liking the idea of the Hypnotic Wings being more effective against creatures with darkvision, so how about we particularly persecute drow by adding "If a creature has Fey Ancestry and sees the Hypnotic Wings with darkvision, the trait does not give the creature advantage on saving throws against being charmed by the wings."

I also mused about including other advantageous traits, e.g. "If a creature has Fey Ancestry or Magic Resistance and sees the Hypnotic Wings with darkvision, the traits do not give the creature advantage on saving throws against being charmed by the wings." That felt like going too far though.

The only question is where do I stick the sentence in!

Tag it on the end as a separate parapraph?

 Hypnotic Wings #A. The mammoth underdark damselfly swirls its wings in a hypnotic pattern. Every creature within 300 feet of the damselfly that can see the wings and is not another underdark damselfly must succeed on a DC 14 Wisdom saving throw or be charmed until the wings' motion ends. The mammoth underdark damselfly must take a bonus action on its subsequent turns to continue the hypnotic motion. It can stop its hypnotism at any time. The hypnotism ends if the damselfly is incapacitated or flies more than 60 feet on its turn (including any distance it moves with Dashing Flight or Dodging Flight). While charmed by the mammoth underdark damselfly, a creature is incapacitated and does nothing but stare mesmerized at the insect. The hypnosis effect ends if the target takes any damage from the mammoth underdark damselfly. If a charmed creature takes damage from a source other than the damselfly or is about to face another obvious danger, such as an approaching fire, it can repeat the saving throw. A charmed creature can also repeat the saving throw at the end of each of its turns. If the saving throw is successful, the effect ends on it. A creature that successfully saves is able to resist the hypnotism for the next 24 hours. If the creature fails a saving throw during their period of resistance against the mammoth underdark damselfly's Hypnotic Wings, it is only partially charmed and may target the damselfly with harmful abilities or magical effects. Instead of being incapacitated, a partially charmed creature has disadvantage on attack rolls and skill checks, and the mammoth underdark damselfly has advantage on attack rolls against the partially charmed creature.
 If a creature has Fey Ancestry and sees the Hypnotic Wings with darkvision, the trait does not give the creature advantage on saving throws against being charmed by the wings.
​

Stick it in the middle as a separate paragraph?

 Hypnotic Wings #B. The mammoth underdark damselfly swirls its wings in a hypnotic pattern. Every creature within 300 feet of the damselfly that can see the wings and is not another underdark damselfly must succeed on a DC 14 Wisdom saving throw or be charmed until the wings' motion ends.
 If a creature has Fey Ancestry and sees the Hypnotic Wings with darkvision, the trait does not give the creature advantage on saving throws against being charmed by the wings.
 The mammoth underdark damselfly must take a bonus action on its subsequent turns to continue the hypnotic motion. It can stop its hypnotism at any time. The hypnotism ends if the damselfly is incapacitated or flies more than 60 feet on its turn (including any distance it moves with Dashing Flight or Dodging Flight). While charmed by the mammoth underdark damselfly, a creature is incapacitated and does nothing but stare mesmerized at the insect. The hypnosis effect ends if the target takes any damage from the mammoth underdark damselfly. If a charmed creature takes damage from a source other than the damselfly or is about to face another obvious danger, such as an approaching fire, it can repeat the saving throw. A charmed creature can also repeat the saving throw at the end of each of its turns. If the saving throw is successful, the effect ends on it. A creature that successfully saves is able to resist the hypnotism for the next 24 hours. If the creature fails a saving throw during their period of resistance against the mammoth underdark damselfly's Hypnotic Wings, it is only partially charmed and may target the damselfly with harmful abilities or magical effects. Instead of being incapacitated, a partially charmed creature has disadvantage on attack rolls and skill checks, and the mammoth underdark damselfly has advantage on attack rolls against the partially charmed creature.
​

Merge them together?

 Hypnotic Wings #C. The mammoth underdark damselfly swirls its wings in a hypnotic pattern. Every creature within 300 feet of the damselfly that can see the wings and is not another underdark damselfly must succeed on a DC 14 Wisdom saving throw or be charmed until the wings' motion ends. If a creature has Fey Ancestry and sees the Hypnotic Wings with darkvision, the trait does not give the creature advantage on saving throws against being charmed by the wings. The mammoth underdark damselfly must take a bonus action on its subsequent turns to continue the hypnotic motion. It can stop its hypnotism at any time. The hypnotism ends if the damselfly is incapacitated or flies more than 60 feet on its turn (including any distance it moves with Dashing Flight or Dodging Flight). While charmed by the mammoth underdark damselfly, a creature is incapacitated and does nothing but stare mesmerized at the insect. The hypnosis effect ends if the target takes any damage from the mammoth underdark damselfly. If a charmed creature takes damage from a source other than the damselfly or is about to face another obvious danger, such as an approaching fire, it can repeat the saving throw. A charmed creature can also repeat the saving throw at the end of each of its turns. If the saving throw is successful, the effect ends on it. A creature that successfully saves is able to resist the hypnotism for the next 24 hours. If the creature fails a saving throw during their period of resistance against the mammoth underdark damselfly's Hypnotic Wings, it is only partially charmed and may target the damselfly with harmful abilities or magical effects. Instead of being incapacitated, a partially charmed creature has disadvantage on attack rolls and skill checks, and the mammoth underdark damselfly has advantage on attack rolls against the partially charmed creature.
​

Or do it as two paragraphs, with the additional sentence at the end of the first?

 Hypnotic Wings #D. The mammoth underdark damselfly swirls its wings in a hypnotic pattern. Every creature within 300 feet of the damselfly that can see the wings and is not another underdark damselfly must succeed on a DC 14 Wisdom saving throw or be charmed until the wings' motion ends. If a creature has Fey Ancestry and sees the Hypnotic Wings with darkvision, the trait does not give the creature advantage on saving throws against being charmed by the wings.
 The mammoth underdark damselfly must take a bonus action on its subsequent turns to continue the hypnotic motion. It can stop its hypnotism at any time. The hypnotism ends if the damselfly is incapacitated or flies more than 60 feet on its turn (including any distance it moves with Dashing Flight or Dodging Flight). While charmed by the mammoth underdark damselfly, a creature is incapacitated and does nothing but stare mesmerized at the insect. The hypnosis effect ends if the target takes any damage from the mammoth underdark damselfly. If a charmed creature takes damage from a source other than the damselfly or is about to face another obvious danger, such as an approaching fire, it can repeat the saving throw. A charmed creature can also repeat the saving throw at the end of each of its turns. If the saving throw is successful, the effect ends on it. A creature that successfully saves is able to resist the hypnotism for the next 24 hours. If the creature fails a saving throw during their period of resistance against the mammoth underdark damselfly's Hypnotic Wings, it is only partially charmed and may target the damselfly with harmful abilities or magical effects. Instead of being incapacitated, a partially charmed creature has disadvantage on attack rolls and skill checks, and the mammoth underdark damselfly has advantage on attack rolls against the partially charmed creature.
​

Hmm… the first two look a bit clunky but #C and #D are alright.

Any preferences?

If not, I'll go for Hypnotic Wings #D.

 

[Cleon]

As you might have guessed from me mucking around with Darvision Hypno-Damsels, I've finished the first draft of the Dragonfly Nymph:

Odonatid, Giant (Giant Dragonfly Nymph)
Medium beast, unaligned
Armor Class 15 (natural armor)
Hit Points 39 (6d8 + 12)
Speed 30 ft., swim 10 ft.

STR​	DEX​	CON​	INT​	WIS​	CHA​
16 (+3)​	15 (+2)​	14(+2)​	1 (–5)​	12 (+1)​	5 (–2)​

Skills Stealth +6
Senses blindsight 10 ft., passive Perception 11
Languages —
Challenge 1 (200 XP) Proficiency Bonus +2

Surprise Ambush. In the first round of a combat, the dragonfly nymph has advantage on attack rolls with its death mask against any creature it surprised. If it hits with its death mask, the surprised target must succeed on a DC 13 Strength saving throw or be knocked prone. If the target is prone, the nymph can make one bite attack against it as a bonus action.

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage.

Death Mask (Recharge 4–6). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) piercing damage and the creature is grappled (escape DC 13).

Jet Dash (Recharge 4–6). The dragonfly nymph swims up to 80 feet.


Description

Tigers of the Water. ???.
A cluster of dragonfly nymphs.

VARIANT: BIG GIANT DAMSELFLY NAIAD

(Monster designed by Casimir Liber and Cleon on Enworld.org's General Monster Talk Creature Catalog Forum; based on the giant dragonfly nymph that first appeared in EX2 The Land Beyond the Magic Mirror (1983) by Gary Gygax.)

Also done the stats for the Dainty, Diminutive and Titanic Giant Odonatids, which took way less time than I expected.

Updating the Dainty Giant Damselfly.
Updating the Diminutive Giant Dragonfly.
Updating the Giant Damselfly.
Updating the Giant Dragonfly Nymph.
Updating the Giant Dragonfly.
Updating the Imperial Giant Dragonfly.
Updating the Mammoth Helicopter Damselfly.
Updating the Titanic Tropical Dragonfly.

EDIT: Just updated the Want List of Monstrous Arthropods and the Index of 5E Monster Arthropods.

Also forgot to allow for the Titanic Underdark Damselfly also having hynowings and spell resistance like the Mammoth version, so have updated the Titanic Tropical Dragonfly accordingly.

 

[Cleon]

Surprise Ambush. In the first round of a combat, the dragonfly nymph has advantage on attack rolls with its death mask against any creature it surprised. If it hits with its death mask, the surprised target must succeed on a DC 13 Strength saving throw or be knocked prone. If the target is prone, the nymph can make one bite attack against it as a bonus action.

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage.

Death Mask (Recharge 4–6). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) piercing damage and the creature is grappled (escape DC 13).

Jet Dash (Recharge 4–6). The dragonfly nymph swims up to 80 feet.

After some reflection, I polished the traits and actions to become:

Special Traits
Ambusher. In the first round of a combat, the dragonfly nymph has advantage on attack rolls against any creature it surprised.

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage and the target is grappled (escape DC 13). Until this grapple ends, the target is restrained, and the dragonfly nymph can't bite another target.

Death Mask (Recharge 4–6). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) piercing damage. If the target is a Large or smaller creature, the target is grappled (escape DC 13) and must make a DC 13 Strength saving throw. On a failure, the target is knocked prone, and the nymph can drag the target closer and make one bite attack against it as a bonus action. Until this grapple ends, the nymph cannot use its Death Mask attack again.
​

Updated the Giant Dragonfly Nymph.

 

[Cleon]

I did wonder about giving the Giant Dragonfly Nymph Speed 20 ft., swim 10 ft., with the Giant Damselfly Naiad having Speed 20 ft., swim 30 ft.

The 2E AD&D original had MOVE 9 on its legs and Swim 3.

In the end I opted to go for a 30 ft. land speed, since an AD&D Crocodile has MV 6" which suggests the Nymphs and Naiads might be a bit faster than the 20 ft. land speed of a Fifth Edition Crocodile.

 

[Cleon]

Remembered something I was planning to add to the Underdark Damselfly but forgot to put in the Description.

I've amended the Mammoth Helicopter Damselfly as follows.

 Ghost and Phantom Larvae. The main reason the drow have failed to exterminate the mammoth underdark damselfly is ghostwings and death phantoms are actually the same species. The larvae of underdark helicopter damselflies larvae can metamorphose into adulthood from a range of instars (larval growth stages) far wider than any natural odonatid, with adult sizes ranging from a Small ghostwing to a Huge death phantom. To eradicate the mammoth underdark damselflies would thus require slaying every ghostwing in the Underdark and destroying all their eggs and naiads. The drow are unaware of this, and the task is nearly impossible even if they knew.
 After mating, female underdark helicopter damselflies lay their eggs in water to hatch into the next generation of naiads, which become adults when environmental cues trigger their transformation. In general, naiads who live alongside larger predators transform into adulthood as early as possible, becoming ghostwings and flying to somewhere safer, explains why the underdark giant damsels' commonest adult size is the ghostwing. However, the most successful naiads will grow into one of these "larger predators" themselves before becoming old enough to metamorphose into adults, in which case they attempt to reach Huge size and become death phantoms.
 Underdark helicopter damselfly naiads can become intermediary adults between a ghostwing and death phantom in size, but this is unusual. This typically only happens when their water pool is just big enough for a single naiad to develop into a Large underdark helicopter damselfly, a creature dubbed a Wraithwing by the surface dweller who discovered it (see Imperial Giant Dragonfly for statistics).
 An underdark damselfly's eggs can survive out of water for an impressive length of time, lying dry and dormant until conditions are better. In addition, underdark damselfly naiads are incredibly adaptable, able to live in an extremely wide range of water temperature and chemistry, from near-boiling brine to crystal-clear icewater, and are also amphibious, able to breathe air as well as water. While they prefer to live in water, an underdark damselfly naiad only has to be submerged when it hatches from its egg, or when a naiad of Large size or bigger needs to molt its exoskeleton and grow into its next instar (see Mammoth Helicopter Damselfly Naiad for details).
 Tied to Eldritch Deeps. Underdark helicopter damselflies have become dependent on the Underdark's mystic radiations. Without regular exposure to its eldritch glow they wither and perish in weeks, which becomes days if they contact the light of the surface world. Daylight or moonlight will cause the corpse to rapidly decompose into useless waste, much like how some drow equipment cannot abide the touch of the sun.
​

Also worked out the numbers for most of the Larvae, but there's two things I'm conflicted about.

Details will be in my next post once I've updated the Nymphs and Naiads.

 

[Cleon]

Also worked out the numbers for most of the Larvae, but there's two things I'm conflicted about.

Details will be in my next post once I've updated the Nymphs and Naiads.

Okay, that took longer than expected but I've finished the updates.

Will post links to all the Odonatids to make it easier to look at them, although I've only updated the Naiad and Nymph entries:

Updating the Dainty Giant Damselfly.
Updating the Dainty Giant Damselfly Naiad.
Updating the Diminutive Giant Dragonfly.
Updating the Diminutive Giant Dragonfly Nymph.
Updating the Giant Damselfly.
Updating the Giant Damselfly Naiad.
Updating the Giant Dragonfly.
Updating the Giant Dragonfly Nymph.
Updating the Imperial Giant Dragonfly.
Updating the Imperial Giant Dragonfly Nymph.
Updating the Mammoth Helicopter Damselfly.
Updating the Mammoth Damselfly Naiad.
Updating the Titanic Tropical Dragonfly.
Updating the Titanic Dragonfly Nymph.
​

Overall I like the statblocks, but as mentioned above there's two things I'm conflicted about.

Firstly, I consistently used "giant odonatid" in the adult entries, but in the larval entries I've got "giant damselfly naiad" or "giant dragonfly nymph" as appropriate.

I'm wondering whether to change it to odonatid, like so:

Ambusher. In the first round of a combat, the giant odonatid has advantage on attack rolls against any creature it surprised.

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage and the target is grappled (escape DC 13). Until this grapple ends, the target is restrained, and the giant odonatid can't bite another target.

Death Mask (Recharge 4–6). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) piercing damage. If the target is a Large or smaller creature, the target is grappled (escape DC 13) and must make a DC 13 Strength saving throw. On a failure, the target is knocked prone, and the giant odonatid can drag the target closer and make one bite attack against it as a bonus action. Until this grapple ends, the odonatid cannot use its Death Mask attack again.

Jet Dash (Recharge 5–6). The giant dragonfly nymph swims up to 80 feet.
​

The "giant dragonfly nymph" can stay in Jet Dash since only dragonfly larvae have that action option.

Also thought about changing everything to "larva" or "nymph" like so:

Ambusher. In the first round of a combat, the giant odonatid larva/nymph has advantage on attack rolls against any creature it surprised.

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage and the target is grappled (escape DC 13). Until this grapple ends, the target is restrained, and the giant odonatid larva/nymph can't bite another target.

Death Mask (Recharge 4–6). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) piercing damage. If the target is a Large or smaller creature, the target is grappled (escape DC 13) and must make a DC 13 Strength saving throw. On a failure, the target is knocked prone, and the giant odonatid larva/nymph can drag the target closer and make one bite attack against it as a bonus action. Until this grapple ends, the larva/nymph cannot use its Death Mask attack again.

Jet Dash (Recharge 5–6). The giant dragonfly larva/nymph swims up to 80 feet.
​

But I don't like that so much. Calling them "larva" a bit generic compared to "nymph" or "naiad" plus if I consistently use nymph for the dragonfly larvae and naiad for the damselfly larvae it's a lot clearer which the text is referring to.

Although once I get to the Description I will make clear the terms are actually interchangeable.

 

[Cleon]

Secondly, I'm still dithering over the Speeds.

I am now increasingly tempted to give the Damselflies' Giant Naiad and Mammoth Naiad the same speeds as a Crocodile and Giant Crocodile and then scaling the others to that, like so:

Size​	Damselfly​	Dragonfly​
Dainty	10 ft., swim 20 ft.	10 ft., swim 10 ft., Jet Dash 40 ft.
Diminutive	20 ft., swim 30 ft.	20 ft., swim 10 ft., Jet Dash 60 ft.
Small	20 ft., swim 30 ft.	20 ft., swim 10 ft., Jet Dash 80 ft.
Medium	20 ft., swim 30 ft.	20 ft., swim 10 ft., Jet Dash 80 ft.
Imperial	20 ft., swim 40 ft.	20 ft., swim 20 ft., Jet Dash 100 ft.
Mammoth	30 ft., swim 50 ft.	30 ft., swim 20 ft., Jet Dash 120 ft.
Titanic	30 ft., swim 50 ft.	30 ft., swim 20 ft., Jet Dash 120 ft.

The current version has the Damselfly Naiad speed based on the Crab and Giant Crab, like so:

Size​	Damselfly​	Dragonfly​
Dainty	20 ft., swim 20 ft.	20 ft., swim 10 ft., Jet Dash 40 ft.
Diminutive	30 ft., swim 30 ft.	30 ft., swim 10 ft., Jet Dash 60 ft.
Small	30 ft., swim 30 ft.	30 ft., swim 10 ft., Jet Dash 80 ft.
Medium	30 ft., swim 30 ft.	30 ft., swim 10 ft., Jet Dash 80 ft.
Imperial	30 ft., swim 30 ft.	30 ft., swim 10 ft., Jet Dash 100 ft.
Mammoth	40 ft., swim 40 ft.	40 ft., swim 20 ft., Jet Dash 120 ft.
Titanic	40 ft., swim 40 ft.	40 ft., swim 20 ft., Jet Dash 120 ft.

Which do you prefer? I keep on vacillating.