Star Trek: Discovery kept fans guessing throughout its sophomore season, which included such surprises as the Red Angel, Spock's curious return, Dr. Culber's resurrection, and the shocking appearance of Burnham's mother.

While not usually appearing in such quick succession, other unforeseen reveals in Star Trek history proved just as shocking as those featured in Discovery. Let's browse some of these iconic moments that populate the other series.

1. The Original Series - "The Corbomite Maneuver"

The Corbomite Maneuver
Star Trek: The Original Series - "The Corbomite Maneuver"

The U.S.S. Enterprise's tumultuous encounter with the massive First Federation starship Fesarius ended when a pilot vessel broke off from the main superstructure and utilized a tractor beam to take Kirk's crew into custody. The Enterprise eventually gained its freedom, but Kirk chose to send a boarding party to the seemingly incapacitated tug. The alien form who previously appeared to speak for the First Federation turned out to be a dummy, while the actual crew turned out to be a single, childlike humanoid (Balok) who welcomed the Starfleet crew. Balok arranged the entire situation to test Starfleet's intentions and greeted them joyfully after Kirk's team demonstrated genuine and helpful behavior.

2. The Original Series - "Errand of Mercy

Errand of Mercy
Star Trek: The Original Series - "Errand of Mercy"

The Klingon occupation of Organia was proceeding as planned until Kirk and Spock escaped from captivity. Kor executed 200 Organians in retribution, an atrocity that seemed irrelevant to the planet's leaders. Kirk and Spock fought back and infiltrated Kor's headquarters, just as the Federation and Klingon fleets prepared to clash in space. Suddenly, all phasers and starship control systems radiated with a searing heat, forcing the two sides to halt their attacks. The Organians admitted that they paralyzed the military assets and that their species transcended the corporeal world. No harm came to any Organians at any point in the invasion, because their humanoid forms served as mere illusions. Ayelborne and Claymare emanated a blinding light, disclosing their status as beings of pure energy. The seemingly defenseless Organians actually held unimaginable power; they simply chose not to wield it with malicious aspirations.

3. Star Trek: The Motion Picture

Star Trek the Motion Picture
Star Trek: The Motion Picture

V'Ger, an alien entity of unprecedented scale and technology, trapped the refit Enterprise and held Earth's fate at its mercy. The Ilia probe led Kirk and an away team to meet the mighty V'Ger, only for Kirk to come across the ancient Earth satellite, Voyager 6, whose identifying plaque retained debris that only left the letters V, G, E, and R visible. Upgraded by an unknown alien race to accomplish its information gathering expedition, the primitive 20th-Century probe achieved consciousness and contained an unimaginable data storage system.

4. The Next Generation - "Yesterday's Enterprise

Tasha Yar
Star Trek: The Next Generation - "Yesterday's Enterprise"

While investigating a rift in space, the U.S.S. Enterprise-D's complement witnessed a vessel emerge into their sector. Unbeknownst to Picard and his crew, this temporal event compromised their past and created a present dominated by war with the Klingons. The long-dead Tasha Yar regained her Bridge post and attempted to ascertain the incoming ship's identity, which turned out to be the U.S.S. Enterprise-C. The entire sequence disoriented the audience, and introducing the Enterprise-D's predecessor produced even further intrigue.

5. The Next Generation - "The Best of Both Worlds"

Star Trek: The Next Generation - "The Best of Both Worlds, Part 1"

An away team beamed onto a Borg cube to rescue the captured Captain Picard. After forcing the vessel slow impulse by destroying distribution nodes, the Starfleet officers found themselves amid a swarm of Borg drones. Dr. Crusher noticed Picard in the distance and called out to him. As the captain turned to face them, the boarding party saw cybernetic implants and realized that Picard has become assimilated with the Borg. The group returned to the Enterprise without their captain, prompting Riker to order the unthinkable — fire upon the cube with Picard still trapped aboard.

6. The Next Generation - "Redemption

Tasha Yar as a Klingon
Star Trek: The Next Generation - "Redemption, Part 1"

The Romulan involvement in the Klingon Civil War included cloaked supply shipments destined to support the Duras family. Sela, the mission's senior Romulan commander, slowly emerged from the shadows during a meeting with the Duras sisters and looked exactly like Tasha Yar, the Enterprise-D's fallen security chief. The twist captivated viewers, who later learned that Sela's birth occurred due to Captain Picard's decision to send Yar back in time to help the Enterprise-C engage a Romulan attack force.

7. The Next Generation - "Relics

Relics with Scotty
Star Trek: The Next Generation - "Relics"

Somehow Riker and La Forge's discovery that a single survivor suspended in a transporter buffer ended up as their second most interesting find among the U.S.S. Jenolan's 75-year old wreckage. As the matter materialized, the figure revealed itself to be none other than Captain Montgomery "Scotty" Scott. Then again, who else but a miracle worker would have the know-how to modify the transporter in such a fashion?

8. Deep Space Nine - "In Purgatory's Shadow

Bashir, Garak in Purgatory's Shadow
Star Trek: Deep Space Nine - "In Purgatory's Shadow"

Worf and Garak depart Deep Space 9 to search for Enabran Tain and other potential Dominion prisoners in the Gamma Quadrant. Unfortunately, their runabout stumbled upon a hidden Dominion fleet, upon which, its Jem'Hadar soldiers take the two Alpha Quadrant natives into custody. Eventually imprisoned, Worf and Garak found they shared a cell with Tain, General Martok, two Romulans, and a Breen. Just as the situation seemed as strange as possible, the guards brought another Federation prisoner back to the room — a weary Dr. Bashir. The doctor explained that he'd gone to bed during a conference on Meezan IV a month earlier, only to awake in the Dominion facility. The revelation that a Changeling currently roamed Deep Space 9 disguised as Bashir startled the group and left them wondering what nefarious deeds the shapeshifter had already set in motion.

This article was originally published on March 27, 2019.

Jay Stobie is a freelance science fiction writer who contributes articles to the official Star Trek website and Star Trek Magazine. He can be found on Twitter at @CaptStobie and Instagram @JayStobie.

Star Trek: Discovery Seasons 1-4 are currently streaming exclusively on Paramount+ in the U.S. Internationally, the series is available on Paramount+ in Australia, Italy, Latin America, the U.K. and South Korea, as well as on Pluto TV in Austria, France, Germany, Italy, Spain and Switzerland on the Pluto TV Sci-Fi channel. It will also stream exclusively on Paramount+ in Italy, France, Germany, Switzerland and Austria later this year. In Canada, it airs on Bell Media’s CTV Sci-Fi Channel and streams on Crave. STAR TREK: DISCOVERY is distributed by Paramount Global Content Distribution.

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Captain Kirk
Star Trek: The Next Generation
Jean-Luc Picard