Star Trek III Glasses for Taco Bell, Fal-tor-pan.
The fal-tor-pan was a Vulcan ritual designed to reunite a Vulcan’s katra with his or her body. It literally meant “re-fusion” in the Vulcan language. A mediating Vulcan, using his or her inherent telepathic abilities, transferred the katra into the original body. The ritual was considered very dangerous, both to the recovering deceased person, and to the keeper of the katra. For this reason, it was almost never performed, and, in 2285, it was in doubt that the ritual had ever been performed at all.
Fal-tor-pan details courtesy of Memory Alpha.