Bone Weaver

Weave Of The Dead: The bone weaver can consume the bones of a dead creature and store them to be spun into sharp webs of bones. These webs are special as they deal 1d6 peircing damage whenever a creature toucheds the web.

Action: 

Bite: +4 to hit, 1d4 piercing damage. When bit, the target must make a DC 10 constitution saving throw or be injected with venom that causes 1d6 necrotic damage and the target becomes prone.

Pounce: When a creature is within 15 feet of the bone weaver, the target must make a DC 13 dexterity saving throw or be grappled by the bone weaver and take 1d4 piercing damage every round with a +4 to hit at advantage. If a creature is still grappled by the bone weaver at the end of it's turn, the bone weaver can take a reaction to make another attack on the grappled creature for 1d4 peircing damage with a +4 to hit. 

Scavenge Bones: If a creature dies within 30 feet of the bone weaver, the bone weaver can take an action to scavenge the dead body for bones to gain a premanent +1 to it's AC. If the bone weaver takes 5 damage to it's HP, it can replenish it's HP and lose this permanent +1 AC.

Echo of the arachnid: The bone weaver can take a bonus action to make a shrill call to summon an arachnid, and any willing spider-type creature within 100 feet can be summoned on the beginning of the bone weaver's first turn. The summoned creature is automatically slotted underneath the bone weaver in initiative. The bone weaver cannot use this ability again until the spider has been killed or removed from initiative.

Attack of opportunity: The bone weaver can take an opportunity attack.

Web Strike: If the bone weaver has a creature that is hostile towards it disengages from it, the bone weaver can attempt to make a dexterity check[roll]1d20+4[/roll] to try and web the creature to a surface. If the creature is webbed, it must take 1d6 piercing damage and be incapacitated.