X is hard to come up with a word for to be sure. I could have gone with Xeno or Xenomorph like so many others but that's not my style. If everyone's going right, I need to see what's on the left.
Xiphoid means 'shaped like a sword'. It is also the common use, colloquial term for any type of retractable blade weapon, the likes of which are often seen in the Sci-Fi/Fantasy/Action genres we gamers tend to enjoy. Most often a xiphoid is wrist mounted and is used to pop a weapon into the users hand.
In my D&D-But-Not milieu (as well as a few other campaign universe's I've had) the Xiphoid is an entity vaguely resembling a humanoid but essentially a pile of magical swords. Animated by the powerful mystic forces imbued into these enchanted blades, the collected weapons stand up and a Xiphoid is born. The Xiphoid primary purpose appears to be adding more and more blades to it's form and will actively hunt down any magical sword it senses, slaying the wielder and throwing the weapon into the whirling, sliding, clanging mix.
The truth of the Xiphoid is a bit more complex. Several of the swords in a Xiphoid are always intelligent. The ego of each intelligent sword wants to be in charge of the Xiphoid and therefore the entity is constantly at war with itself. It's movements are not but the sound of hilts and blades striking the ground as it walk but the clashing of swords as they hit each other within the floating humanoid heap.
The swords with the most powerful egos try to convince other swords that they should be in charge and always want to add allies to their 'army' within the creature. This is the reason they hunt down and add new swords whenever possible.
The Xiphoid possesses the powers and abilities of all the swords in its collected form. It can only use two active abilities at a time and has a to-hit 'bonus' the is an average of the blades within it (yet another reason to try and add more and better swords). At minimum there are about 9-12 swords in a human sized Xiphoid, though entites of ogre size or large have been heard of containing 20-30 swords. Daggers, knifes, foils and the like are also fair game.