Force Blade (3.5e Equipment)
From D&D Wiki
The Force Blade is a unique +1 ghost touch longsword. Normally, it resembles an ordinary sword hilt made of beautifully carved Mithral or Mithralwood, sometimes with a diamond or dragonshard set into the hilt. In this form, it can be hung from a belt by holding it an inch away, upon which a small loop of force energy will attach it to your belt. This loop of force energy can be deactivated by simply taking hold of the hilt and pulling it away from the belt.
With a command word that requires a free action, the hilt can be activated. When activated, a blade composed of pure force energy materializes, dealing damage as a +1 longsword. In addition to the normal 1d8+1 slashing damage, a Force Blade deals an additional 1d6 points of force damage to ethereal foes (as long as you have some means of seeing them). Note that although the blade extends onto the ethereal plane (and thus allows ethereal foes to disarm you), the hilt does not, meaning that the blade cannot be picked up and used by an ethereal creature unless the hilt is taken onto the ethereal plane (though it has no such special ability to strike foes on the material plane while ethereal, being force energy). The same command word deactivates the blade, returning it to hilt-only form that can be hung from a belt.
The force effect can only stay active for a time equal to the HD of the character wielding it and cannot be activated again until whoever is wielding it has a whole night of sleep (8 hours).
The hilt has hardness 15 and 5 HP (assuming a medium weapon). The blade effectively has unlimited hit points, though it cannot form or maintain its form while within an antimagic field. The sword also usually cannot be sundered with a normal attack (because the hilt is usually too small and within one's hand).
Versions with higher enhancement bonuses are not unheard of. For upgrade and creation purposes, treat a Force Blade as if it had a +3 effective enhancement bonus.
Cost to Create: as a +3 weapon (plus 300 gp for the hilt); Requirements: Craft Magic Arms & Armor, Craft Wondrous Item, Wall of Force or Mordenkainen's Sword
Requirements for Psionic equivalent: Craft Psionic Arms & Armor, Craft Universal Item, Wall of Ectoplasm