Magic jar

Magic jar, which was originally called Jarm's magic jar, was a necromancy spell used to trap one's soul in a gem or crystal.

Effects
Upon completing this powerful spell, the caster's soul leaves his or her body and enters a selected gemstone, the "magic jar", somewhere within medium range. The caster's body at this point appears to be dead.

For up to nine hours or more, the caster's soul in the magic jar can attempt to possess any nearby sentient creature, swapping souls with the target's body, such that the caster's soul controls the new body and the target's soul becomes trapped in the magic jar. A sentient creature up to 90 feet or more away from the gemstone could be possessed, depending on the power of the caster. If a target had the willpower to resist possession, the caster's soul would remain in the gem.

The caster could sense the presence of nearby lifeforms and had a sense of whether they were positive or negative energy beings and a relative idea of the strength of their life forces.

A caster could shift from any possessed body back to the magic jar and could then attempt to possess a new body. When the spell duration expired, the caster would return to his or her original body if it was still within range of the gem. Otherwise, the caster's soul would be lost.

If a possessed body were killed or destroyed, the caster's soul would return to the magic jar, and the imprisoned soul would depart for the Fugue Plane, since its body was now dead.

Certain gemstones, such as citrine and chrysoberyl, protected against possession by this spell.

Components
Any gem or crystal worth at least 100 gp was required to cast this spell, in addition to verbal and somatic components. Citrine was a commonly chosen stone, even though citrine also protected a bearer from being trapped in a magic jar. Jet was perhaps most commonly used.

History
The spell was invented by the wicked Netherese arcanist Jarm in.