Star Trek: The Vulcan Katra
Star Trek Discovery: The Vulcan Katra Explained: https://screenrant.com/star-trek-discovery-vulcan-katra-mind-meld-explained/
”In this moment of utter despair, Burnham experiences a vision of sorts in where she's speaking with her Vulcan mentor, Sarek (James Frain). Only it isn't really a vision or hallucination, but a legitimate means of communication between her and Sarek, happening in real time and across lightyears of space.”
”The telepathic link between Sarek and Burnham is possible because of a piece of Sarek's "katra," his soul or mind essence, exists within Burnham's consciousness. This aspect of Sarek's katra entered Burnham's mind during the mind meld - a telepathic and intimate link between two minds, allowing the involved individuals to exchange thoughts - that the two shared when Sarek found Burnham as a child in the bombed Vulcan Learning Center. And while this iteration of a katra transference is a little different, it is by no means the first time it's happened on Star Trek.”
”Most notably, in the final minutes of Star Trek II: The Wrath of Khan, Spock briefly mind melds with an unconscious Dr. McCoy and transfers to him his katra, knowing he would likely die in his attempt to save the Enterprise and her crew. Spock gave McCoy his katra in the hopes his experience and wisdom would live on even in death, but thanks to the unique circumstances of Spock's burial, his regenerated body and his katra were later able to be reused in Star Trek III: The Search for Spock. In the meantime, McCoy did exhibit some of Spock's mannerisms and would chime in with knowledge only Spock could know, demonstrating just how strongly the effect of holding a Vulcan katra is on a human mind.
This is by no means the only instance in where a Vulcan has transferred their katra to another - Spock previously did this during an episode of Star Trek: The Original Series, 'Return to Tomorrow', briefly sharing his katra with Nurse Chapel in order to more easily expel a being that had taken over his own body, and during episodes of Star Trek: Enterprise, Captain Archer hosted the katra of the most acclaimed Vulcan to have ever lived, Surak, a philosopher and founder of the modern Vulcan civilization.”
