Ascension
Ascension, or transcendence, was a process by which a humanoid or some other corporeal lifeform could be transformed into a being of pure energy through the mastery of psionics or technology. Many cultures, including the Children of Tama, believed in a form of ascension; the Tamarians' ascension process involved florkas. Some Zalkonians believe this transformation to be the pinnacle of evolution.

O'Connor's ascension
Lieutenant jg O'Connor, a Starfleet officer, had an interest in ascension beliefs. O'Connor claimed he had begun a process of "spiritual alignment" in 2370. In 2378, he began work on a sand mandala, which he said would assist him to ascend to a higher form. However, these efforts were largely fake, and were primarily designed to give O'Connor a way to stand out from other Starfleet officers.

In 2380, O'Connor staged an ascension ceremony aboard the . He invited Ensign D'Vana Tendi and seven other crew members to attend the ceremony; when Tendi accidentally destroyed the sand mandala, O'Connor angrily blamed her for ruining his chance to ascend.

Tendi was mortified, and attempted to make up for her error in several ways. First, she tried to give O'Connor a Hiverian metronome, which she said could help his ascension if he relaxed and "let it sync to [his] biorhythms", but O'Connor rejected her offer and destroyed the metronome. Next, she used her vacation days to follow O'Connor around the ship, waving incense and chanting in Latin. She also released florkas near O'Connor, hoping that a syncretic approach would "beat the system." Tendi also offered to align O'Connor's chakra and to "Reiki" him; these offers were also rejected.

When the Cerritos was damaged by terraforming emulsion, O'Connor and Tendi were both placed in jeopardy as a coral reef began to form around the ship's warp core. After Tendi rescued O'Connor, he admitted that he had been faking his planned ascension, and was using Tendi as someone convenient to blame. Subsequently, O'Connor rescued Tendi from a falling rock, becoming trapped himself. After the terraforming effect was reversed, the rock disappeared and O'Connor and Tendi kissed; immediately afterwards, O'Connor began to levitate and glow. He experienced a painful sensation of burning and said, "I don't want to ascend!" His form was surrounded by energy in the pattern of a bird, and as he became pure energy, he experienced visions of Abraham Lincoln and a giant koala (which he said balanced the universe upon its back). Just as he was about to reveal the meaning of life to Tendi, he disappeared. ()

Other examples of transcendence 
Millions of years ago, the Organians existed as humanoids, but over the passage of those same millions of years, they evolved beyond the need for physical bodies. ()

After merging with Humanity, the artificial intelligence, V'ger ascended to a higher plane of existence in a blinding flash of light. ()

While quoting Hamlet to Q, Picard argued that humanity would one day become god-like in status, perhaps rivaling the Q Continuum itself. Irritated by this notion, Q threw a Shakespeare book at Picard and disappeared. ()

A group of Zalkonians manifested increasingly powerful psionic abilities after experiencing some mysterious mutations. The Zalkonian people were frightened by those undergoing the change and their government began exterminating anyone showing symptoms. Eventually, this mutation led to a few members of the Zalkonian race to shed their corporeal forms and evolve into beings of pure energy. ()

In 2374, when Kes began expanding her psionic potential, her psychokinetic abilities, which once laid dormant, started manifesting itself. As her increasingly powerful psychokinetic abilities threatened to tear the USS Voyager apart, Kes left the ship in a shuttlecraft while her atomic structure was destabilizing. She and the shuttlecraft fades in a flash of white light and launches the USS Voyager over 9000 light-years closer to Earth as a parting gift. ()

Captain Benjamin Sisko was led to the Fire Caves on Bajor following the victory at the Battle of Cardassia, where he engaged in a final confrontation with the Pah-wraiths, who were assuming the form of Dukat. Sisko destroyed the evil Book of the Kosst Amojan and trapped Dukat, along with the Pah-wraiths, in the Fire Caves forever. Once Sisko fulfilled his destiny, he materialized in the Celestial Temple, where he must remain to finish the tasks assigned to him by the Prophets. It was prophesized that Sisko's ascension would usher in a new Golden Age for Bajor. ()

Appendices

See also 
 Semi-divine detachment

Background information
Although the word "ascension" was not widely used in this context before , the notion of a humanoid transforming or evolving into a non-corporeal lifeform is a well-established Star Trek trope. The earliest reference may be the Thasian in , who says, "I have taken my form from centuries ago, so that I may communicate with you." More explicitly, in , Ayelborne tells Captain Kirk, "Millions of years ago, Captain, we were humanoid like yourselves, but we have developed beyond the need of physical bodies."

In later series, transformations of this sort are seen in  (the Zalkonian "John Doe") and in  (Kes). In "Moist Vessel", Tendi dismisses Sam Rutherford's comparisons with Q and the Traveler, though the changes undergone by Amanda Rogers (an apparent Human who was revealed to be a member of the Q Continuum in ) and Wesley Crusher (who joined the Traveler to explore different planes of existence in ) are not completely dissimilar from the "ascension" sought by O'Connor.

What is different about the presentation of "ascension" in "Moist Vessel" is the implication that it is something that a Human can achieve through spiritual disciplines.
Ceremonies
Mythology