Seastars with high AC - 5e idea?

[Cleon]

Let's get on with the Description…

Giant brittle stars are enormous ophiuroids related to sea stars and similar starfish. A brittle star has a disc-shaped body from which radiate long flexible arms it uses to catch food, walk and swim; most have five arms but a few species have six. Underneath the arms are sticky tube feet that can manipulate prey or cling to surfaces, such as cliff faces and cave roofs. The writhing motion of its arms gives ophiuroids another name: the serpent stars. Brittlestars, including the giant version, live on the sea floor and can be found in any climate. A few species tolerate brackish water and can live around river mouths.
 A typical giant brittle star has a body disc 4 to 5 feet across and arms 15 to 20 feet long. Bigger specimens are possible but rare; smaller giant brittle stars are commoner but rarely attack humanoids.
 Most kinds of brittle stars are either male or female, although some are both sexes at once or can alternate between male and female; they breed by floating millions of eggs away on the currents. The rare six-armed brittlestar can also reproduce by splitting into two (see the Walking Star described below for an example).
 Predatory Scavengers. A brittle star is primarily a scavenger, sweeping up scraps of food with its arms and conveying it to the five-jawed maw on its underside. A giant ophiuroid is much larger and more active than its normal-sized kin so requires far more food, so giant brittlestars roam around the sea floor and devour anything edible they come across. While it lacks the intelligence to deliberately stalk prey, a giant brittle star will enthusiastically pursue prey for a few minutes if it senses there's a good meal close by.
 Hungry Beachcombers. Air-breathing humanoids most often encounter giant brittle stars on the shoreline as they patrol the tideline for food washed up by the waves. A giant brittlestar can emerge from the water for up to an hour, so coastal specimens often supplement their diet of flotsam with careless or slow land creatures.

 

[Cleon]

VARIANT: BURROWING BRITTLE STAR
A common type of brittle star lives in the silt of the sea floor. It usually hides its body under the mud or sand and reaches out its arms to snag passing food. Such brittle stars have arms that are far longer than species that actively roam about on the surface. A giant burrowing brittle star has the following traits.
 Slow Burrower. The burrowing giant brittle star has Speed 10 ft., burrow 10 ft, climb 10 ft.
 Long Fragile Arms. The burrowing giant brittle star's arm attacks have reach 30 ft. and its Shed Arms is triggered by 6 damage or a Strength of 16 or higher. In addition, the d6 roll to determine what happens is:

1: Nothing else happens.​

2-3: The attacker makes a DC 14 check (Strength for weapon hits, spellcasting ability for magic hits). If they succeed, one arm is severed from the brittle star if it has any arms left.​

4-6: One arm is severed from the brittle star if it has any arms left, but the brittle star takes half damage from the attack that severed the arm.​

The Walking Brittle Star will come later. Hopefully!

 

[Casimir Liber]

Okay, these segments look good and have pasted them in.

 

[Cleon]

Okay, these segments look good and have pasted them in.

Last night I realized there was one passage from the Description's original "in my head" version that I forgot to include: the bristles! I'll amend the first paragraph as follows:

Giant brittle stars are enormous ophiuroids related to sea stars and similar starfish. A brittle star has a disc-shaped body from which radiate long flexible arms it uses to catch food, walk and swim; most have five arms but a few species have six. These creatures have bony spines down the side of their arms whose size and density depends on the species, ranging from stubby bumps to stout spikes or dense bristles. The spines may look formidable but are blunt and harmless, they improve the limbs' traction rather than acting as a defense. Underneath the arms are sticky tube feet that can manipulate prey or cling to surfaces, such as cliff faces and cave roofs. The writhing motion of its arms gives ophiuroids another name: the serpent stars. Brittlestars, including the giant version, live on the sea floor and can be found in any climate. A few species tolerate brackish water and can live around river mouths.​

Updated the Giant Brittle Star (Ophiuroid) with the revised Description and the Burrowing Star.

 

[Cleon]

VARIANT: BURROWING BRITTLE STAR
A common type of brittle star lives in the silt of the sea floor. It usually hides its body under the mud or sand and reaches out its arms to snag passing food. Such brittle stars have arms that are far longer than species that actively roam about on the surface. A giant burrowing brittlestars has the following traits.

Dang it, that should be "burrowing brittle star has" not "burrowing brittlestars has"! Better correct it.

 

[Cleon]

VARIANT: LAND STAR (WALKING BRITTLE STAR)
This mutant version of the giant brittle star has adapted to a terrestrial existence. These six-armed brittlestars can live on any land with a warm or tropical climate, from mangrove swamps to deserts. A land star can survive in cold climates but becomes so sluggish it would have trouble defending itself against a warm-blooded opponent. It cannot survive being frozen. A walking brittle star has an earthy coloration that matches the soil of its environment. If moved to different terrain, it changes color to match over one to three months.
 A land star's limbs are specially adapted for walking and edged with stout flattened spikes. Their gait resembles an insect's – two "tripods" of legs that step forward alternatively – but like all brittle stars, a land star's radial symmetry allows it to walk in any direction with equal facility.
 Landstars are sequential hermaphrodites: that is, under certain conditions they can switch from male to female or vice versa, but they cannot be both sexes at the same time. Their eggs and larvae cannot breathe air so they must spawn in water, so many walking giant brittlestars populations exist around a lake, river, oasis or marsh where they spawn (which obviously requires at least one land stars of each sex). However, they do not need water or a mate to reproduce.
 The rare species of brittlestar with six arms, including the land star, can multiply by fission, splitting their disc-shaped body down the middle to produce two new animals. Land stars that live in dry terrain use this method rather than spawning to sustain their numbers. A land star with the three arms on one side of its body shorter than the other side is probably a youngster produced by fission that has not fully regrown the body half that separated to become its twin sibling.
 A land star has the following traits.
 Amphibious. The land star can breathe air and water (this trait replaces the Water Breathing of the standard giant brittle star).
 Walker. The land star has Speed 30 ft., climb 30 ft., swim 20 ft.
 Six-Armed. A giant brittle star with six limbs instead of five does not gain any extra attacks, but its Shed Arms is triggered by 7 damage or higher and losing arms results in the following speed reduction:
 A six-armed giant brittle star's speed is lowered by 5 ft. if it loses one or two arms and halved if it loses three or four. If it loses five arms its speed becomes 5 feet and if it loses all six it has a speed of 0 feet.
 Fission. During their reproductive season, a six-armed brittle star can split in half to become two new brittle stars, this process is fairly slow and does not inconvenience the creature. For a land star, fission takes ## to ## days (##d##). The two new land stars each have 21 (2d10+10) hit points and three arms. As they gain new arms with their Regrowth ability, their hit points slowly increase to 42 (5d10 + 15) hit points when they develop six full length arms and completely regenerated body-disc. It usually takes at least three months (6d10+60 days) for a split half to grow into a whole six-armed giant brittlestar.

 

[Cleon]

VARIANT: LAND STAR (WALKING BRITTLE STAR)
This mutant version of the giant brittle star has adapted to a terrestrial existence. These six-armed brittlestars can live on any land with a warm or tropical climate, from mangrove swamps to deserts. A land star can survive in cold climates but becomes so sluggish it would have trouble defending itself against a warm-blooded opponent. It cannot survive being frozen. A walking brittle star has an earthy coloration that matches the soil of its environment. If moved to different terrain, it changes color to match over one to three months.
 A land star's limbs are specially adapted for walking and edged with stout flattened spikes. Their gait resembles an insect's – two "tripods" of legs that step forward alternatively – but like all brittle stars, a land star's radial symmetry allows it to walk in any direction with equal facility.
 Landstars are sequential hermaphrodites: that is, under certain conditions they can switch from male to female or vice versa, but they cannot be both sexes at the same time. Their eggs and larvae cannot breathe air so they must spawn in water, so many walking giant brittlestars populations exist around a lake, river, oasis or marsh where they spawn (which obviously requires at least one land stars of each sex). However, they do not need water or a mate to reproduce.
 The rare species of brittlestar with six arms, including the land star, can multiply by fission, splitting their disc-shaped body down the middle to produce two new animals. Land stars that live in dry terrain use this method rather than spawning to sustain their numbers. A land star with the three arms on one side of its body shorter than the other side is probably a youngster produced by fission that has not fully regrown the body half that separated to become its twin sibling.
 A land star has the following traits.
 Amphibious. The land star can breathe air and water (this trait replaces the Water Breathing of the standard giant brittle star).
 Walker. The land star has Speed 30 ft., climb 30 ft., swim 20 ft.
 Six-Armed. A giant brittle star with six limbs instead of five does not gain any extra attacks, but its Shed Arms is triggered by 7 damage or higher and losing arms results in the following speed reduction:
 A six-armed giant brittle star's speed is lowered by 5 ft. if it loses one or two arms and halved if it loses three or four. If it loses five arms its speed becomes 5 feet and if it loses all six it has a speed of 0 feet.
 Fission. During their reproductive season, a six-armed brittle star can split in half to become two new brittle stars, this process is fairly slow and does not inconvenience the creature. For a land star, fission takes ## to ## days (##d##). The two new land stars each have 21 (2d10+10) hit points and three arms. As they gain new arms with their Regrowth ability, their hit points slowly increase to 42 (5d10 + 15) hit points when they develop six full length arms and completely regenerated body-disc. It usually takes at least three months (6d10+60 days) for a split half to grow into a whole six-armed giant brittlestar.

Hmm, this is different enough it might work better as an entirely separate entry to the regular aquatic Giant Brittle Star.

What do you think?

 

[Casimir Liber]

Yeah I was just thinking that - totally different environment etc. We also end up with hugely long description section....

 

[Cleon]

Yeah I was just thinking that - totally different environment etc. We also end up with hugely long description section....

Yes, how about changing the Variant subentry to be for Six-Armed Brittle Stars and do the Land Star as a separate monster?

That'll require a minor tweak to the Giant Brittle Star (Ophiuroid) Description from:

 Most kinds of brittle stars are either male or female, although some are both sexes at once or can alternate between male and female; they breed by floating millions of eggs away on the currents. The rare six-armed brittlestar can also reproduce by splitting into two (see the Walking Star described below for an example).

To:

 Most kinds of brittle stars are either male or female, although some are both sexes at once or can alternate between male and female; they breed by floating millions of eggs away on the currents. The rare Six-Armed Brittle Star (see below) can also reproduce by splitting in two.​

The Six-Armed Variant entry can be as follows. I've polished the wording up a bit from the Land Star Variant's rough draft.

VARIANT: SIX-ARMED BRITTLE STAR​

A few species of brittle star have six arms instead of the usual five. These animals can multiply by fission, splitting their disc-shaped body down the middle to produce two new animals, although they are still capable of reproducing normally. A six-armed star with the three arms on one side of its body shorter than the other side is probably a youngster produced by fission that hasn't regrown the half that formed its twin sibling.​

 A six-armed brittle star has the following traits.​

 Fission. During their reproductive season, a six-armed giant brittle star can split in half to become two new brittle stars; this slow process takes 10 to 20 (2d6 + 8) days but does not inconvenience the creature. The two new brittle stars each have 21 (2d10+10) hit points and three arms. As they gain new arms with their Regrowth ability, their hit points slowly increase until they reach 42 (5d10 + 15) hit points when they grow six full length arms and a complete body-disc. It usually takes at least three months (6d10+60 days) for a split half to regenerate into a whole six-armed giant brittlestar.​

 Six Arms. A giant brittle star with six limbs instead of five does not gain any extra attacks, but its Shed Arms is triggered by 7 damage or higher (5 if it has the Fragile Arms trait) and losing arms reduces its speed as follows:​

 A six-armed giant brittle star's speed is lowered by 5 ft. if it loses one or two arms and halved if it loses three or four. If it loses five arms its speed becomes 5 feet and if it loses all six it has a speed of 0 feet.​

 If the brittle star finishes a long rest its arm stumps regrows enough to remove one "arm's worth" of speed reduction, so its is lowered by 5 ft. with two or three arms, halved with four or five lost arms, and reduced to 5 ft. if is has lost all six arms. The brittle star regains its speed and arm attacks when its Regrowth trait replaces the lost arms.​

I'll update the Giant Brittle Star (Ophiuroid) with the above.

That just leaves doing the Land Star as a separate entry, which shouldn't be that troublesome.

EDIT: And the Land Star is done (see below). Left the Giant Brittle Star (Ophiuroid)'s Six-Armed Variant in Red while waiting for your feedback.

 

[Cleon]

Land Star (Walking Giant Brittle Star)
Large beast, unaligned
Armor Class 15 (natural armor)
Hit Points 42 (5d10 + 15)
Speed 30 ft., climb 30 ft., swim 20 ft.

STR​	DEX​	CON​	INT​	WIS​	CHA​
14 (+2)​	8 (–1)​	16 (+3)​	1 (–5)​	9 (–1)​	3 (–4)​

Saving Throws CON +5
Skills Stealth +3
Condition Immunities blinded, charmed, deafened
Senses Blindsight 60 ft., passive Perception 9
Languages —
Challenge 1 (200 XP) Proficiency Bonus +2

Amphibious. The land star can breathe air and water.

Capable Clambering. A land star ignores difficult terrain penalties caused by slippery or smooth surfaces and can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Fission. During their reproductive season, a land star can split in half to become two new land stars; this slow process takes 10 to 20 (2d6 + 8) days but does not inconvenience the creature. The two new land stars each have 21 (2d10+10) hit points and three arms. As they gain new arms with their Regrowth ability, their hit points slowly increase until they reach 42 (5d10 + 15) hit points when they grow six full length arms and a complete body-disc. It usually takes at least three months (6d10+60 days) for a split half to regenerate into a whole walking giant brittlestar.

Regrowth. If a land star loses an arm, organ or other body part and survives, it regrows the lost body parts as it heals. It takes 15 (1d10 + 10) days for a land star to replace a missing arm.

Rudimentary Vision. The land star has disadvantage on Wisdom (Perception) checks that rely on sight. It perceives patterns of light and darkness and can only see the silhouette or shadow of a creature or object; it can not see colors or fine details.

Shed Arms. Whenever the land star takes at least 7 damage at one time from an attack that required a Melee or Ranged Attack roll, or if the land star is grappled by a creature that is Large size and/or possesses a Strength of 18 or higher, roll a d6 to determine what happens.

1-2: Nothing else happens.​

3-4: The attacker makes a DC 15 check (Strength for weapon hits, spellcasting ability for magic hits). If they succeed, one arm is severed from the land star if it has any arms left.​

5-6: One arm is severed from the land star if it has any arms left, but the land star takes half damage from the attack that severed the arm.​

In addition, a land star can choose to deliberately tear off one of its own arms as a reaction (see Auto Dismemberment).
 If a land star loses an arm to a grapple attack or self mutilation, the land star takes 4 (1d4 + 2) damage or the damage rolled by the attack, whichever is higher.
 A severed arm flops and writhes about for 1d10 rounds as it dies. The arm is unable to attack or grapple and has a speed of 5 feet. The land star has no control over its severed arms.
 A land star's speed is lowered by 5 ft. if it loses one or two arms and halved if it loses three or four. If it loses five arms its speed becomes 5 feet and if it loses all six it has a speed of 0 feet.
 If the land star finishes a long rest its arm stumps regrow enough to remove one "arm's worth" of speed reduction, so it is lowered by 5 ft. with two or three arms, halved with four or five lost arms, and reduced to 5 ft. if it has lost all six arms. The land star regains its speed and arm attacks when its Regrowth trait replaces the lost arms.

Option: A land star with a shortened, partially regrown arm might be able to attack with it, but the arm attack will have a 5 ft. reach or 10 ft. reach instead of the 15 ft. reach of a full length arm.

Actions

Multiattack. The land star can make up to three attacks against different targets: it can make one attack with its bite against a target it is grappling, the remaining attacks must be arm attacks. If the land star has fewer than three arms because of its Shed Arms ability, the maximum number of arm attacks it can make equals its current number of arms.

Arm. Melee Weapon Attack: +4 to hit, reach 15 ft., one target. Hit: 4 (1d4 + 2) bludgeoning damage. If the target is a creature, it is grappled (escape DC 14; with disadvantage on escape checks). Until this grapple ends, the target is restrained, and the land star can't use that arm to attack a different target. If the arm hits a target that is already grappled, the target must succeed at a DC 14 Strength check or be pulled within reach of the land star's bite attack, or into the nearest empty space if that isn't possible.

The land star has six arms (unless it lost some due to its Shed Arm trait), each of which can grapple one target.

Bite. Can only attack grappled targets. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 4 (1d4 + 2) bludgeoning damage plus 4 (1d4 + 2) slashing damage.

Reactions

Auto Dismemberment. A land star can automatically lose an arm (see Shed Arms) as a reaction in order to escape a dangerous situation. For example, if the ophiuroid is being attacked by a creature larger than itself or has its hit points reduced to 20 of fewer.


Description
This mutant version of the giant brittle star has adapted to a terrestrial existence. These six-armed brittlestars can live on any land with a warm or tropical climate, from mangrove swamps to deserts. A land star can survive in cold climates but becomes so sluggish it would have trouble competing with fast warm-blooded rivals. They cannot survive being frozen solid. A walking brittle star has an earthy coloration that matches the soil of its environment. If moved to different terrain, it changes color to match over one to three months.
 A land star's limbs are specially adapted for walking and edged with stout flattened spikes. Their gait resembles an insect's – two "tripods" of legs that step forward alternatively – but like all brittle stars, a land star's radial symmetry allows it to walk in any direction with equal facility.
 Landstars are sequential hermaphrodites: that is, under certain conditions they can switch from male to female or vice versa, but they cannot be both sexes at the same time. Their eggs and larvae cannot breathe air so they must spawn in water. Therefore walking giant brittlestars populations are often centered around a lake, river, oasis or marsh where they breed (which obviously requires at least one land stars of each sex). However, land stars do not need water or a mate to reproduce.
 Like other brittlestars with six arms, landstars can multiply by fission, splitting their disc-shaped body down the middle to produce two new animals. Land stars that live in dry terrain use this method rather than spawning to sustain their numbers. A land star with the three arms on one side of its body shorter than the other side is probably a youngster produced by fission that has not fully regrown the parent's body half that separated to form its twin sibling.

(Original monster designed by Casimir Liber and Cleon on the Creature Catalog Monster Homebrews forum)