10 "No Body, No Death" Cases In Star Trek
6. Sybok
Spock's half-brother was last seen walking into the eye of a non-corporeal being, demanding that it share its pain. That being was shot by a Klingon Bird-Of-Prey moments later, so one could assume that Sybok went to the great Sha-Ka-Ree in the sky with it, end of story.
Although, is it truly the end of the story? We never actually saw Sybok die, rather we merely saw him becoming one with said entity. Although a barrage of Klingon disrupters is generally quite good at reducing anything to dust, the very fact that there's a question of corporeal status means that Sybok's survival is possible.
What if, in this new state, Sybok actually survived the encounter, and was left behind at the centre of the galaxy? Now that Star Trek: Prodigy has shown us that Starfleet propulsion systems have come on leaps and bounds since The Final Frontier, someone ought to check if that laughing Vulcan is sat on a rock, flinging stones around, and waiting for a starship to come to save him.