Possession occurs when one being takes control of a body which is not its own.
Possession is different from alternative personalities like Kal-El or Kal, facets of Clark Kent's personality which come out under different circumstances. It is also different from mind control, where one person is able to take control of another through hypnosis, magic, or other means.
Possession is one of the more commonly used plot device on Smallville. For example, Lana Lang was possessed several times by Margaret Isobel Thoreaux while Lionel Luthor has been possessed by Jor-El, and Lex Luthor by General Zod. Clark Kent has been possessed by teenager Dawn Stiles, and Chloe Sullivan has been possessed by Dawn Stiles, Gretchen Winters, Madelyn Hibbins and Siobhan McDougal.
After the possession is over, the person who was possessed often has no memories of what happened, but not always. For example Lex knew that he had been possessed by Zod. When Lex was kidnapped, he was forced to tell how he got his powers.
There are many known ways to achieve possession:
Kryptonian spirits are able to possess human bodies, which they refer to as a "vessel". This form of possession usually requires some sort of preparation ahead of time, often done by a third party (or by a Kryptonian object):
- Jonathan Kent made a deal with Jor-El at the start of Season Three to give him Kryptonian powers to enable him to get a red kryptonite-infected Clark back from Metropolis. During this time Jonathan was in control of his own mind and simply possessed Jor-El's powers. However, after this Jor-El was spontaneously able to possess Jonathan for short periods, such as in Talisman where he channels Jor-El's powers to heal Clark from a stab wound.
- After Lionel Luthor was exposed to the Crystal of Water in Season Four, he became a vessel for the artificial entity Jor-El to use in the event that Clark needed his aid. For example, when Clark was shot by Gabriel Duncan and died in Season 5, Jor-El possessed Lionel, giving his body Kryptonian powers in order to retrieve Clark. After Clark was restored, Jor-El left Lionel's body and the possession ended. Lionel still seems to serve as Jor-El's vessel; in Oracle, Lionel was able to blast away Brainiac (who was in the form of recently deceased Jonathan Kent) with Jor-El's power. Lionel's connection to Jor-El remained into Season 7, as Zor-El used crystals to locate Jor-El's vessel and found Lionel in his offices. However, after the events of Oracle, Lionel merely maintained Kryptonian knowledge and could write Kryptonian but was never again truly possessed.
- Throughout the last half of Season Five, Brainiac prepares Lex Luthor to become a vessel for General Zod, a Kryptonian trapped in the Phantom Zone. After Zod possessed Lex's body, Zod and Clark fought on Earth. Clark returned General Zod to the Phantom Zone using the Crystal of El, and Lex's possession was lifted. It is unclear whether Zod would be able to use Lex as a vessel again, if he were to escape the Phantom Zone.
- In Season Eight's Bloodline, Faora, the second wife of General Zod, escapes the Phantom Zone and possesses the body of Lois Lane. Kara Kent uses the Martian crystal to cast Faora out of Lois' body.
Kryptonian technology also enables body transfers, where two people switch bodies. In many ways, this acts as a two way possession.
- In Season Four's Transference, Lionel and Clark switched bodies when one of them touched the other while holding the Crystal of Water. After they switched back, Lionel had no memories of the transfer.
Other Alien Possession
Several non-Kryptonian Zoners who lack bodies seem to be able to possess humans at will.
- In Season Six's Fallout, a Zoner named Baern possessed a human named Lamar, and did battle with Clark at the Kent Farm and the Fortress of Solitude. Clark later used the Crystal of El to send Baern back to the Phantom Zone, and Lamar recovered from the possession, with no memory of Clark's powers, or the last six weeks of his life.
- In Season Six and Seven, the phantom Bizarro possessed a series of humans - starting with a tourist in Argentina, and inhabiting a new body every day. His human hosts were only able to survive for 24 hours. Eventually Bizarro sampled Clark's DNA, and was able to create a body of his own. His last known human host was Philipe Lamont, who fully recovered from the possession with no memories of what happened while he was possessed.
- In Season Six's Labyrinth, Zoner Dr. Hudson attempts to gain control of Clark's body by making him reject his Kryptonian heritage as a figment of his imagination. He almost succeeds but is defeated by the Martian Manhunter.
- After being severely damaged by Baern, Brainiac eventually managed to regenerate himself and possess Casey Brock. He remained there until he could repair himself, after which he attacked Chloe Sullivan. However, not anticipating her meteor power that protected her and depowered Brainiac, a part of Brainiac was transferred into Chloe, which gradually presented itself during the start of Season Eight. In order to take full possession of Chloe, Brainiac started to delete her memories. Clark thought he had managed to save Chloe by taking her to the fortress, however, Brainiac was then also able to infect the Fortress of Solitude and wait there for Doomsday to bring Chloe back for Brainiac to take full possession of Chloe. The Legion extracted the metallic nanites to save Chloe.
- Darkseid is an incorporeal being that had the ability to possess some living or even non-living beings.
- Parallax is a parasitic fear entity that can possess his victims by making them give into fear and use them as puppets to serve his goals.
Witches have the ability to cast spells which allow them to possess the bodies of human beings.
- After Lana visits the tomb of the witch Countess Margaret Isobel Thoreaux, a Mark of Transference appeared on Lana's back. This mark forced Lana to serve much like a Kryptonian vessel, allowing Isobel to possess Lana seemingly at will.
- In Season Four's Spell, Isobel casts a spell to allow the spirits of her fellow witches to possess Lois and Chloe. After Clark destroyed Isobel's spellbook, Lana's, Lois', and Chloe's possessions were all lifted, however, Isobel returned to Lana's body in Sacred and Commencement.
Several humans have acquired the power of physical possession upon their death, through the power of kryptonite.
- In Season Four's Spirit, Dawn Stiles was a teenager who acquired the ability of possession when she died by crashing her car into Carlton George - which contained kryptonite. Dawn projected her spirit astrally, and when her astral spirit overlapped with Martha Kent's body, she possessed Martha. Once she had a physical body, Dawn was also able to possess Lois Lane, Lana Lang, Chloe Sullivan, Clark Kent, and other Smallville High students; she seemed to require physical touch in order to be able to transfer her spirit to a new entity.
- In Season Five's Tomb, Chloe was possessed by Gretchen Winters, a teenager who was wearing a bracelet with a kryptonite gem when she was murdered. Chloe became possessed when she touches Gretchen's bracelet. Gretchen was later able to transfer her spirit into her murderer, when he touched her bracelet. She then killed his body with his own hand, ending the possession and freeing her spirit.
- In Season Nine's Escape, Chloe Sullivan, Lois Lane and another lady were possessed by the vengeful spirit of Siobhan McDougal. Siobhan's spirit was eventually released when Lois scratched into the paint of Bevan McDougal (But behind this painting, has the painting of Siobhan). She first entered into a guest of the McDougal Inn, who was with her boyfriend, causing her to kill him. Much later, Chloe is possessed by the spirit of Siobhan in the forest, having physical contact with the possessed girl. Siobhan (in the body of Chloe) has just crossed his path with Clark. While he takes a shower, she comes in and tries to seduce him, but he refuses any kind of relationship. Lois comes in and suddenly faced with Clark holding the arms of "Chloe," Lois gets jealous and delivers a beauty cream to Siobhan and has physical contact with her, causing her to be what possessed by the spirit. After crossing paths with Oliver, she knocks him down and turns into her true form, a form of Banshee.
- When Lois holds Isis's amulet to the sun, she is subsequently possessed by the spirit of Isis. Clark Kent arrives where Isis/Lois was, and soon after he reveals to Isis/Lois that he is the Blur, but Isis does not care and says, "This vessel may once have been called Lois, but now serves Isis," and flies in front of Clark. Then she goes to the Metropolis museum by ripping open a metal door and she heads towards a crate containing Osiris' heart and rips off the lid. Clark arrives at the Watchtower and tells Oliver Queen that Isis has disappeared with Osiris' heart, both Tess and Oliver inform him that she might be headed for the Metropolis museum to reunite Osiris' heart with his body. Isis is preparing to bring Osiris back to life, but when she opens the sarcophagus, Isis only sees dirt and starts crying. Clark comes in and tells her it is over.
Isis declares that it cannot be over because their love is eternal and that Clark knows nothing about love. She then proceeds to push him onto the sarcophagus and binds him down, getting ready to sacrifice him to Osiris. Cat Grant who watch her from distance is shocked and she accidentally knocks a statue over and breaks it. Isis turns and Cat runs away when she bumps into Green Arrow. She senses Oliver behind her and notes that he doesn’t want to hurt Lois' body and then throws an energy ball at him, which he dodges. Oliver reveals to Clark that the only way to trap Isis is for the sun to hit the amulet again, thus trapping her spirit. Isis again throws an energy ball at Oliver long enough for Clark to break free of his restraints and grab Osiris' heart. Clark threatens to destroy the heart unless Isis releases Lois. Isis, seeing no hope, attempts to stab herself. Oliver fires an arrow at the amulet, sending it towards Clark, who uses his heat vision on the amulet, retrapping Isis in the amulet and freeing Lois.
- Each possession is usually done by an entity lacking a physical body: a Phantom Zone wraith, a Kryptonian spirit, a dead human, or a dead witch. The exceptions are body transfers using Kryptonian technology, in which two bodies exchange spirits, and the time when Dawn Stiles was still comatose, but her spirit was able to leave her body.
- Chloe Sullivan has been possessed by the most spirits: Dawn Stiles, Gretchen Winters, and Madelyn Hibbins.
- Lana Lang has spent the most time being possessed; Countess Margaret Isobel Thoreaux possessed her in three separate episodes in Season 4.
- Chloe and Lois were possessed by five different people.
- Out of all the main cast throughout the series, Pete Ross, Whitney Fordman, Jason Teague, Jimmy Olsen, Kara Kent, and Tess Mercer are the only characters who have never been possessed (or exchanged spirits through a body transfer).