A "Karma Houdini" is a villain who is never punished (or is insufficiently punished) for their evil actions by the end of a story, thus escaping justice and "pulling a Houdini" (disappearing) from the way of karma. As such, when the story is over, this villain is not really defeated; he/she remains in position to continue his/her misdeeds, either towards the protagonists or a new target or, in the most extreme cases, is still as much of a threat as he/she was before, or even worse.

This also concerns corporations, organizations or teams who are not disbanded at the very end of the story, thus they are still able to pose a threat even if some of their majors or agents were killed or imprisoned (e.g. Dead Tube).

IMPORTANT:

• By definition, a Karma Houdini is the strict opposite of a Scapegoat.
• Deceased and Presumed Decesed villains usually do not count as Karma Houdinis; the only way for a dead or presumed dead character to count is if the death/presumed death is of natural causes (e.g. Former Head Trancy, Dmitri Desgoffe-und-Taxis, Steele, Donald Love, Warren T. Rat and Nefretiri).
  • And the same goes for Redeemed Villains who've discovered redemption have no need to have this category, while they're under Redeemed.
  • Undead villains who were killed, but returned and continue to commit atrocities without punishment may also qualify in certain circumstances (e.g. Hatbox Ghost).
    • This also applies to villains who were slain, but were completely brought back to life and escaped punishment as well. (e.g. Frieza, Chucky and Evolt).
• Regardless of how painless their imprisonment, Imprisoned villains do not count as they are unable to pose a physical threat (outside their confinement). Of course, former inmates who successfully escape imprisonment can count.
• Villains whose status is dependent upon player choice cannot qualify unless they do not receive punishment for their actions in any possible ending of the game.

A Karma Houdini happens when:

1. The villain is thwarted but not aptly punished in the resolution. This often happens when a villain is simply humiliated or harmed in a comical manner, but only faces a temporary punishment when they deserve worse, not enough to prevent them from striking again in the next episode, season or installment. Examples: Sugar from Total Drama and Darlene from Gravity Falls.
2. The villain makes an escape at the story's climax. Probably the most common type. Often, the villain escapes while the heroes are preoccupied with some other danger (usually that they created), sometimes because, in most stories, preventing whatever disaster was caused by a villain is more important than going after the villain himself. Sometimes this is done to set up a sequel, or at least leave the story open for one. However, this does not count when they do get their just desserts in the sequel/final installment. An example is Hannibal Lecter.
3. The villain simply exits the story after performing their action, and is not encountered by the hero again. This usually occurs with minor antagonists (as opposed to central ones), as the most common scenario for this type of Karma Houdini is that the protagonist simply escapes the villain, who is not seen again because they are not relevant to the rest of the story. Examples: Honest John Worthington Foulfellow, Gideon, Stromboli and the Coachman in Disney's Pinocchio, Scratcher from Rudolph and Frosty's Christmas in July, Bomb Voyage from The Incredibles and DJ from Star Wars.
4. The villain is forgiven at the last second, without being truly redeemed. These villains spend the story causing strife, but when the conflict is over, the protagonists do not bear them any ill will, and in some case welcome them into their group of friends. They do stop doing evil, but never apologize and do not display any intention to bettering themselves, and their misdeeds are swept under the rug. Examples: Aro in Twilight Saga or The Misfits in Jem and the Holograms.
5. The villain outright wins at the end of the story, defeating the hero (or other villains) and succeeding in all their evil plans. For extremely obvious reasons, this is, by far, the least common type and can reasonably be expected to occur only in the very darkest of stories, and is in fact very common in modern horror stories. Examples: Mai Mashiro, Audrey II in the most common ending of Little Shop of Horrors, Anton Chigurh in No Country for Old Men, Noah Cross from Chinatown, Rustal Elion in Mobile Suit Gundam IRON-BLOODED ORPHANS, the Fruit Winders Gang in all of their comic strips and Bagul in Sinister.
6. The villain is more of a jerk and thus many don't see the need to punish them (in general, they punish themselves). These kinds of villains are usually from sitcoms, children's cartoons or even racing films (If the protagonist wins) and thus are not really threats. Because of this, many heroes simply let the villain do what they want. Example: Chick Hicks from Cars.
7. The villain is ousted and/or exiled but not brought to justice. These villains are driven out by the hero or some other force of good, but is not aptly defeated. Examples: Idi Amin, Doc Hopper, Puffy Fluffy, Sergeant Crushida Pepper, Agatha Trunchbull and Parker Selfridge.

However, in some cases, not all Karma Houdinis are meant to be hateable, taken seriously and/or always evil. Some can have redeeming qualities or reasonable motives for their actions (e.g. Felonious Gru, Cassandra and Hawk Moth). Some can even be remorseful, mischievous, anti-villains, chaotic neutrals or even extremists (e.g. most Trevor Henderson villains, David 8, Billie227, Honest John Worthington Foulfellow and Gideon).

However, in the worst case scenario, some Karma Houdinis can be Pure Evil (e.g. Frieza, Art the Clown, Chucky, Anton Chigurh, Noah Cross, Taurus Bulba, Pinocchio, Glitchtrap, Cipher, Nyarlathotep, the Rake, Steele, Rasmin Yelkov, SCP-4666, Scarlet King, Warren T. Rat, Mr. Widemouth, the Doctor, the Coachman, Mr. Grasping, Freddy Krueger, Toplofty and O'Bloat, Takaaki Tenjo, Evolt, Ultraman Tregear, the Clown, the Duke, Slender Man, the Water Street Butcher and Josh). These types of Karma Houdinis (and very well being the most infamous examples of all), should they not get punished for their actions, will eventually lead to a sad or bad ending at the end of a story, novel and/or series.