Web Pool. An Arachniddi can create and use webbing, but not indefinitely. Arachniddi have up to 120ft of webbing ready for use.

During a short rest, a player can roll a 1d10 per player level to regain webbing, and recovers all expended dice and webbing after a long rest.

 At level 1, you are able to hurl forth a web from spinnerets hidden within your legs as an action. Choose two of the following when choosing this race:

Webweaver. As an action, you can begin weaving an intricate web from your spinnerets. This web can extend up to a total of 120 feet. You determine what to do with the webbing when you begin spinning it choosing from Message or Webbed Ward.

Message. You can weave a web in a manner of intricate signs only arachniddi understand, conveying messages a few sentences long for each 5 feet of webbing. Each 5 foot of webbing beyond the first 5 feet requires an additional action to create

Webbed Ward. The web you spin trails behind you as you move, creating a continuous line of 5-foot wide webbing on the floor that follows the path you move in or in the air so long as you attach each side of the webbing. This webbing is considered difficult terrain and you may use it as a bridge if you fly or jump a distance, leaving the webbing behind you (the web supporting your weight). You might also use the web to ward an area, touching the web to be alerted when another creature passes over it.

Webbed Attack. The attack has a recharge of 5-6. This is a ranged weapon attack. The attack bonus equals your proficiency modifier + your Dexterity modifier. The attack has a range of 30 feet and targets one Large or smaller creature. This uses 15ft of webbing.

On a hit, the creature is restrained by webbing. As an action, the restrained creature can make a DC 11 Strength check, escaping from the webbing on a success. The effect also ends if the webbing is destroyed. The webbing has AC 10, 5 hit points, vulnerability to fire damage, and immunity to bludgeoning, poison, and psychic damage.

Webbed Escape. You can hurl your webs exceedingly far, up to 120ft in a straight, unobstructed line. When the web reaches an obstacle it ends and adheres to that obstacle. The web functions as a rope, allowing you to climb up, down, or across it. If you attach one end of the web to a solid surface and hold onto the other end, you may also be able to swing on this web.

 At level 8, you gain the Web Prison action.

Web Prison. As an action, you can cocoon a incapacitated large creature and lower in lethargic webbing. A cocooned creature cannot recover from the incapacitated status until removed from the cocoon. If the Cocoon is damaged, the creature can roll a constitution saving roll, if the result is equal or higher then the characters level, they break free from the cocoon with half heath regenerated if they were defeated in battle, otherwise they have whatever health they received prior to being cocooned.   

Cocooning a small creature takes 15ft of webbing, 25ft for a medium creature, and 45ft for a large creature. 

As a bonus action, you can grow flesh on your arachnid-like face and chitinous body that makes you appear as though you are of any Humanoid race the same size as you of your choice. You can remove the disguise as a bonus action, tearing the false flesh away. Your arachnid-like legs are not covered in this disguising flesh, but are able to retract into your body as part of this bonus action, melding with your flesh. This effect is not magical but physical and takes 5 minutes. 

As an action, shed your false skin to show your true arachnid nature in all its glory. Creatures who witness this violent shed must save a wisdom saving throw of 12 or gain the frightened condition until the start of their next turn. The player takes 1d4 force damage.

The player can do this action an once per short rest as its painful to shed the false skin in this manner. 

You ignore movement restrictions caused by webbing. Additionally, while in contact with a web, you know the exact location of any other creature in contact with the same web.

You have a climbing speed of 30 feet. When using your arachnid legs, you can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

At level 5, You begin to generate lethargic venom, and can bite an enemy to inflict poison status effect. You gain access to the Vicious Bite action

Vicious Bite. As an action, bite your enemy to inflict the poison status effect. A creature subjected to this poison must succeed on a DC 13 Constitution saving throw or be poisoned for 1 minute. A creature who succeeds the saving throw is immune to the characters poisoned effect for 24 hours, but can still take poisoned damage.

At level 9, you can induce a lethargic poison in your body. When using the Vicious Bite action on a enemy under 20% health, you can incapacitate them without further damage. The save DC is a constitution saving roll of 15.

Enemies who succumb to the poison will awaken after 1d4 minutes. You can only use this venom twice per long rest as its taxing on your body to create. 

At level 10, your arachnid arms have become more sturdy as your chitinous skin has adapted to combat. As a bonus action, you can use your arachnid arms to slash at the enemy.  

Increase your Intelligence or Dexterity score by 1, and your Charisma score by 2

You are a Humanoid. You are also considered a Monstrosity for any effect or prerequisite that requires you to be a Monstrosity.

You can see in dim light within 60 feet of you as if it were bright light and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

You can fluently speak Common and Undercommon. You can communicate with spiders as if you shared a language and can also communicate via your Webweaver trait.

Arachniddi age very slowly, they typically reach what they consider adulthood at 100 years, and live for up to 1,000 years on average.

Arachniddi stand between 5 and 6 feet tall when walking on their Humanoid legs, and 7 to 8 feet tall when walking on their arachnid ones.

 Your base walking speed is 30 feet when using your Humanoid legs, and 40 feet when using your arachnid ones.