Aetherstrike

You gain a +1 bonus to attack and damage rolls made with this magic weapon. Additionally, when you hit with a melee attack using this magic spear and reduce the target to 0 hit points, you gain 2d6 temporary hit points. It has the following additional properties:

While wielding this spear, You can take a Bonus Action to cause your armor to assume the appearance of a normal set of clothing or some other kind of armor. You decide what it looks like—including color, style, and accessories—but the armor retains its normal bulk and weight. The illusory appearance lasts until you use this property again or doff the armor.

 

Leveling weapon:

The spear only as powerful as the energy it absorbs. To unlock the spear’s true power the spear must continue to absorb more and more power, unlocking powerful abilities (Max 100).

Power of the enemy.

Prerequisite: Absorb 25 Hit Points.

The spear gains the returning weapon property when thrown. 

Psi Warriors power.

Prerequisite: Absorb 50 Hit Points

When you use one of your Psionic energy dice you may re-roll the result of the dice once the new result must be used even if its lower. 

Spirit of the Enemy.

Prerequisite: Absorb 75 Hit Points.

The number of hit points you gain increases to 3d6. Additionally, you can expend 25 absorbed hit points to cast the conjure volley spell without the need for material components. Doing so downgrades the spear one tier, requiring you to absorb an additional 25 hit points before the spear regains this trait.

Gift of the Enemy.

Prerequisite: Absorb 100 Hit Points.

Instead of gaining temporary hit points you may use the hit points you absorb to steal one skill, resistance or ability from the target. The effects of this trait last until you take a long rest or until you use this trait again.

Surge of power.

Prerequisite: Absorb 100 Hit Points.

You can expend all your absorbed hit points to permanently increase the power  of this weapons attack and damage rolls by +1 to maximum +3. Doing so downgrades the spear to tier 0.

Proficiency with a Spear allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Requires Attunement by a Psi Warrior, Damage, Combat, Thrown, Versatile, Sap