Voyage to the Bottom of the Sea (1964)

S02E26 The Return of the Phantom

Captain Krueger comes back to force Nelson into shooting Crane. After the deed is done, Krueger inhabits Crane’s body and sets out to find a new host for Lani, his deceased lover, in hopes of reuniting with her. Now, Admiral Nelson must find a way to rescue his friend and thwart Krueger's sinister intentions once and for all.