Silken Spite

From Explorer's Guide to Wildemount, pages 277-278.

Description
Weapon (rapier), artifact (requires attunement).

The blade of this rapier is made of spider silk. Its onyx pommel is tipped with a ruby cut in the shape of a spider, and the blade carries the blessing of Lolth.

Sentience. Silken Spite is a sentient chaotic evil weapon with an Intelligence of 13, a Wisdom of 15, and a Charisma of 15. It has hearing and darkvision out to a range of 120 feet.

The weapon communicates telepathically with its wielder and can speak, read, and understand Abyssal, Common, Elvish, and Undercommon.

Personality. A murderous yochlol named Sinnafex lives within Silken Spite. The weapon speaks in whispers, pushing its wielder to trust no one and to kill those who cause the slightest personal offense.

Dormant. The rapier grants the following benefits in its dormant state:
 * The rapier has one minor beneficial property and one minor detrimental property.
 * You can speak, read, and write Abyssal, Elvish, and Undercommon.
 * You have darkvision out to a range of 60 feet. If you already have darkvision, being attuned to the rapier increases the range of your darkvision by 60 feet.
 * You can use an action to cause poison to coat the rapier's blade. The poison remains for 1 minute or until an attack using this weapon hits a creature. That creature must succeed on a DC 13 Constitution saving throw or become poisoned for 1 hour. If the saving throw fails by 5 or more, the creature is also unconscious while poisoned in this way. The creature wakes up if it takes damage or if another creature uses its action to shake the creature awake.
 * While carrying the rapier, you can move up, down, and across vertical surfaces and upside down along ceilings, while leaving your hands free. You have a climbing speed equal to your walking speed. Additionally, you can't be caught in webs of any sort and can move through webs as if they were difficult terrain.

Awakened. When the rapier reaches an awakened state, it gains the following properties:
 * The rapier gains an additional minor beneficial property and an additional minor detrimental property.
 * The weapon's bonus to attack and damage rolls increases to +2.
 * The saving throw DC for the weapon's poison increases to 15.
 * While holding the rapier, you can use an action to cast one of the following spells from it (save DC 15): Cloudkill, Darkness, Levitate, or Web. Once a spell has been cast using the rapier, that spell can't be cast from the rapier again until the next dawn.

Exalted. When the rapier reaches an exalted state, it gains the following properties:
 * The rapier gains a major beneficial property.
 * The weapon's bonus to attack and damage rolls increases to +3.
 * The saving throw DC for the weapon's poison and spells cast from the weapon increases to 17.
 * Magical darkness doesn't impede your darkvision.
 * While holding the weapon in dim light or darkness, you can use a bonus action to teleport up to 60 feet to an unoccupied space you can see that is also in dim light or darkness. This property can't be used again until the next dawn.