CURRENT STATUS:

DEAD

Tuvix was created in a transporter accident that
combined Tuvok and Neelix into a single person.
He retained the memories and knowledge of both of them.
He lived among the crew for many weeks until a procedure was developed that would separate him back into Tuvok and Neelix. Tuvix contented that he would be murdered if the separation occurred, and because of that the Holodoc would not do it. Captain Janeway performed the separation and Tuvix ceased to exist. His entire life span was shown in the episode "Tuvix".