Mythallar

This magical device looked much like a crystal ball but was about 150 feet in diameter. The globe shed a very bright light—similar to the disc of the sun—with dimmer shadows and shapes moving across its surface. An ornate stand kept the perfectly spherical device in place.
Touching a mythallar was a lethal decision. Anyone who touched the device was instantly slain. Any item that touched it, except the stand that contained it, was instantly disintegrated. Any undead that touched the mythallar were destroyed. The only known way a mythallar could be destroyed is by a disintegrate spell.

Utility

Mythallars allowed arcanists to create quasimagical items(an item that acted as a permanently activated magical item, provided that it remained within range of a mythallar) without draining their lifeforce. Most quasimagical items were actually created with the commonfolk in mind, simple creations to assist in the everyday tasks of the middle class. The first such items to enter the markets were roomlights, tiny globes that lit up upon command. Magical provision of running water and plumbing followed after.
Its function was a simple one—it converted raw magic from the Weave and sent that power throughout a city to provide the magical energies required for the continued operation of quasimagical items. The mythallar had an effective range of one mile. Therefore, if a city was larger than one mile in diameter, it had to have more than one mythallar. When a quasimagical device was within the effect of the mythallar, it gained the ability to use the magical powers that had been imbued into it. Outside the area‚ quasimagical devices ceased to function as magical devices.

Inventor(s)

Ioulaum, an archwizard from Netheril is credited with the creation of the mythallar. However, since the fall of Netheril and Ioulaum's decent into lichdom, a small boy by the name of Petavor had discovered the means by which to create the giant mass of Weave. This boy then encountered Booglesnoot Luthaxen, who then took this knowledge for himself, but not without erasing the knowledge from the boy's mind. Unbeknownst to Booglesnoot, the boy learned from a very powerful outsider, and this entity gave the knowledge to build a mythallar back to Petavor.

Access & Availability

Mythallar are incredibly rare, if not unique items. There are less than a handful known to exist.

Complexity

Mythallar are very simple in terms of functions, but creating one requires a massive amount of magic.