the Arachnid possesses the proportionate powers of a spider, granted to him from an irradiated Common House Spider (Achaearanea tepidariorum) which bit him that was apparently already mutated from prior exposure to certain frequencies of radiation, a surge of wild magic, arcane or scientific experimentation and received a final, lethal dose during his introduction to the tradition. The radioactive, complex mutagenic enzymes in the spider's blood that were transferred at the time of the bite triggered numerous body-wide mutagenic changes within the monk, granting him superhuman strength, speed, toughened flesh, and numerous arachnid-like abilities. That mutation granted him an "enhanced chromosome pattern".

Some sages said  that this powers were not of scientific origin, but were a sign that they had become a totemic avatar of the Web of Life and Destiny. While somo monks initially struggled to accept this, they later came to the conclusion that both were plausible, and has had they powers mystically augmented on a number of occasions.

Tools of the Trade

When you adopt this specialization at 3rd level, you gain proficiency with alchemist's supplies and Weaver's Tools. If you already have this proficiency, you gain proficiency with one other type of artisan's tools of your choice. In addition, you can use Replicate Magic Item infusion to recreate Wand of Web, Ring of Feather Falling (2nd-Level Artificer). Ring of Feather Falling, Spider Staff (6th-Level Artificer), Wand of Binding, Wand of Viscid Globs (10th-Level Artificer), Cloak of Arachnida, Ring of Evasion (14th-Level Artificer),

Arachnid Spells

3rd-level Arachnid feature

You always have certain spells prepared after you reach particular levels in this class, as shown in the Arachnid Spells table. These spells count as artificer spells for you, but they don't count against the number of artificer spells you prepare.

Armorer Spells

Artificer Level	Spell
3rd	Entangle, Zephyr Strike
5th	Hold Person, Pass without Trace
9th	Nondetection, Slow
13th	Aura of Life, greater invisibility
17th	Steel Wind Strike, Hold Monster

 

As an Arachnid Artificer, you use your new enhanced physiology, webs, wits, and gadgets when you cast your spells. When describing your spellcasting, think about how you're using a tools and powers to perform the spell effect. 

Spider Suit

3rd-level Arachnid feature

 

Your experimentations of the spider powers have led to you making armor a conduit for your magic. As part of a long rest, you can turn a suit of armor you are wearing into Spider Suit, provided you have Alchemist's Supplies and Weaver's Tools in hand.  The armor continues to be Spider Suit until you make another suit of armor or you die.

You gain the following benefits while wearing this armor:

• When you make attack a weapon, you can use your Dexterity modifier, instead of Strength modifier, for the attack and damage rolls.
• Your unarmed strikes can deal bludgeoning damage equal to 1d6.
• When you take the Attack action on your turn, you can use your bonus action on that same turn to make a single unarmed strike attack.
• The armor attaches to you and can't be removed against your will. It also expands to cover your entire body, although you can retract or deploy the helmet or mask as a bonus action. 
• You can integrated or remove some specifics magic items to the armor as an action: Rope of climbing, Rope of Entanglement, Wand of Web, Wand of Binding, Wand of Viscid Globs, Slippers of spider climbing, Cloak of Arachnida ,Goggles of night, Ring of jumping. Ring of Feather Falling, Ring of Evasion, Spider Staff.
• The maximum number of items you can infuse at once increases by 1, but those extra items must be part of your Spider suit.

A integrated item is absorbed by the armor and its functions still can be access by the suit If a integrated item requires attunement, you must attune to the item before you can use it. However, the Spider Suit and the attached item count as a single magic item with regard to the number of magic items you can attune to. If you remove the item from the suit of armor, your attunement to the item ends.

Arachnid manifestations

at 3rd level, you learn due your Spider Powers and engineer prowess to use some items in new and interesting ways when you has them integrated

 Rope of climbing or  Rope of Entanglement

Webslinger:
As an attack or as an bonus action, you may target a surface, object or creature within a distant equal to your movement speed. If the target is Small or Smaller, you can make a Strength (Athletics) grappling check to pull it to you and grapple it. Alternatively, if the target is Medium or larger, you can choose to be pulled to it, however, this does not grapple it, when use in this way you can use as a move action and you can chain it together in a elegant and continuous fashion similar to fly except that you need to be within your range of a target. in addition, you can use this ability as a reaction when you fall to pull yourself up to 10 feet in any direction.

Slippers of spider climbing or Cloak of Arachnida 

Spider Reflexes: 
you have advantage on Dexterity checks and have resistance to falling damage (half the falling damage before apply others reductions) , additionally,  by expending a spell slot of level 1 or above as a Reaction to take the Dodge action.

Goggles of night

Enhanced Senes:
you can effectively see anything that isn't behind total cover, even if you're blinded or in darkness. Moreover, you can see an invisible creature within that range, unless the creature successfully hides from you.

Ring of jumping

Spider Leap:
the distance of your long and high jumps increases by 15 feet (this increment is in the base jump so you can multiply it. this extra distance costs movement as normal).

Ring of Feather Falling

Featherweight Fighting:
While you are wielding only light weapons, your movement speed increases by 10 feet and you gain a +2 bonus to your damage rolls, so long as you are not wearing medium armor, heavy armor, or wielding a shield.

Ring of Evasion

Evasive Footwork:
When you move, ,you can roll a d8 and adding the number rolled to your AC dexterity saving until the start of your next turn. You can use this trait a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

Slippers of spider climbing, Ring of jumping. Ring of Feather Falling and Ring of Evasion (All integrated together at the same time)

Enhanced Spider Reflexes: 
you can nimbly dodge out of the way of certain area effects, such as a red dragon's fiery breath or an ice storm spell. When you are subjected to an effect that allows you to make a Dexterity saving throw to take only half damage, you instead take no damage if you succeed on the saving throw, and only half damage if you fail.

Wand of Viscid Globs

The glob don´t dissolves instantly if exposed to sunlight instead after 1 minute of exposure, also been integrated into the suit negate the risk of destruction by sunlight exposition of the wand

Cloak of Arachnida, Spider Staff or Wand of Web

Webcrawler:
When in Web of any kind you can walk through the web without penalty.in any direction. In addition, when you cast the Web spell, by expending a spell slot of level 1 or above. If you do this, you don´t need to concentrate on it.

Spider Staff

Wallcrawler:
You when the Spider Climb Spell, on yourself by expending a spell slot of level 1 or above. If you do this, you don´t need to concentrate on it. and you double its duration, in addition you can cast it as a Reaction

Spider Staff

• If you aren't wielding any weapons or a shield when you make the attack roll, Your unarmed strikes d6 becomes a d8.
•  Your unarmed strikes It deals 1d6 extra poison damage on a hit when used to make a unarmed strikes.
•  Whenever an unarmed strike hits an object, the hit is a critical hit.

Cloak of Arachnida, Spider Staff, Slippers of spider climbing and Wand of Web (All integrated together at the same time)

Spider Metamorphosis:
You can use a bonus action to magically assume the form of any Spider whose challenge rating is equal to or less than your level  You must follow all the other rules for Wild Shape as detailed in the druid class description. 

You can stay in Spider form for up to one hour, at which point you revert to your normal form. You can revert to your normal form earlier if you use a bonus action to do so, or if you fall unconscious, you drop to 0 hit points, or you die.

Once you use your Spider Metamorphosis feature you must finish a short or long rest before you can Spider Metamorphosis again.

Extra Attack

Starting at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn. Moreover, you can cast one of your cantrips in place of one of those attacks.

Spider Physiology

5th-level Arachnid feature

Proportional strength of a spider: You count as two size larger when determining your carrying capacity and the weight you can push, drag, or lift and you triple your jumping distance. additionally, you have advantage on Strength checks and Strength saving throws.

Enhanced Immune System:  You have advantage on saving throws you make to avoid or end the poisoned condition on yourself. You also have resistance to poison damage.

Spider Suit Upgrade

9th-level Arachnid feature 

The maximum number of items you can infuse at once increases by 2, but those extra items must be part of your Spider suit.

 

Spider-Sense

15th-level Arachnid feature

a precognitive danger or "spider" sense which warns him of potential or immediate danger by the manifestation of a tingling sensation in the back of his skull, and links with his superhuman kinesthetics, enabling him to evade most any injuries unless he cognitively overrides his automatic reflexes. The precise nature of this sense is unknown,

You gain the ability to cast Foresight Spell on himself as a action. Once you cast a spell in this way, you can't do so again until you finish a long rest.