Detachable Lower Half

This person is putting his abilities to good use

In Real life, people can survive bifurcation, but the lower body can't survive because the nerves are no longer being connected to the brain and it lacks a source of oxygenated blood, therefore victims need either Prosthetics on the lower body area or have to use a wheelchair for mobility. In Fiction, on the other hand, people can survive without a lower body and the lower body survives without being attached to the back nerves and blood vessels: not only that, but they can also reunite both halves and become whole again. Unlike Losing Your Head regrowing it never happens. Sometimes used as a superpower, and rarely uses psychic powers to control it. Usually used as an ability.

It is usually justified for robots, because they either have a power source that keeps the lower body and upper body to keep going even when separated from the hip, or might have a normal core processor (which is the most common case). The Undead may also exhibit this ability to have the upper body and lower body apart.

See: Helping Hands, Detachment Combat.

Examples of Detachable Lower Half include:

Advertising

There are two commercials that play this trope the most bizarre way possible; one happens to Males, another to Females.
A commercial of unknown reason on PubliTv.com titled Goody's Por Partes.
A shower gel commercial by the name Lactacyd has this happen to two girls.

Anime And Manga

Subverted in Naruto with Suigetsu in the anime-only expansion of Chapter 347 called "Zebuza's Blade".
Den, the leader of Barjack from Battle Angel Alita, is... well, not a cyborg, but a separate personality of another character who operates a drone body via radio waves; he maintains two different lower bodies, a humanoid one and a horse-like one, which makes him resemble a centaur when he uses it. It's a bit of a mystery why, since he's about twelve stories tall and attaching the two halves of his body is a big operation.

Comics -- Books

Wolverine's upper and lower halves become separated in Ultimate Wolverine vs Hulk.

Films

Happen in the Not Safe for Work C-Budgeted movie Erotic Ghost Story 2 In the climax of the movie where 2 Demons are having a threesome with a woman which is at first a Foreshadowing of what happens a few minutes after where she REALLY gets split in half by the Big Bad male demon called Wu Tung and like the foreshadowing both halves are still alive and she pleads for her lower half back because of her no longer feeling arousal due to both halves being no longer attached, once Wu Tung notices another girl who was watching who is out to stop him he stops and tells the girl in half to put herself back together.

Live Action TV

Happens to Amanda in episode 39 of The Amanda Show when her lower half runs away from her offscreen because "It doesn't like the pants" while her upper half says floating and completely oblivious of what happened until one of the audience members points it out to her, She then asks for someone to find her lower half then one of the employees walks over to her with her lower half where she explains to why it left and then has both halves taped back together.

Myths & Legends

Manananggals of Filipino Mythology are vampires with this ability. The upper half detaches at night and flies away to feed (a favorite treat is using its long tongue to feast on fetuses); if it does not rejoin the lower half by daybreak, the manananggal dies.
- The best way to prevent the manananggal from becoming whole is to sprinkle either salt or garlic on the lower half which remains stationary during its nightly sortie.

Video Games

Gimghamphatts from Onimusha 2 does this during the last boss fight.
Metroid Prime Hunters: Weavel can do this, with his lower body functioning as a turret.
The Harvester from Dragon Age: Origins - Golems of Amgarrak is a massive boss who detaches the large lower part of its body when it goes One-Winged Angel.
In at least one of he Teenage Mutant Ninja Turtles Video Games, Krang will attack this way. Justified in that it's an android body.
In the SNES classic Chrono Trigger, many of the bosses upper and lower halves that act independently of each other, and have different strengths and weaknesses.

Western Animation

Commander Hoek and Leutenant Stimpy have this happen in the episode "Black Hole" of Ren and Stimpy.
Star Trek: The Animated Series episode "Bem". The titled alien (Ari bn Bem) can detach parts of his body, including his head and lower torso.
Megabyte from ReBoot does this on occasion, usually to sit in his Cool Chair.
In Phantom 2040 Hubert Graft detaches his lower half from his everyday legs to an attack droid. It is quite clear from his reaction that doing this is quite painful for him.
Rushu from Wakfu can do this. And ironically can travel much faster because of it.
Tends to happen in Tex Avery cartoons.