Tag-Team Twins

Twins are natural Tag Team partners in Professional Wrestling. Besides having all that creepy twin stuff going for them, they also have one trick few other wrestlers (save masked ones) can match -- they can easily swap places in a match behind the ref's back, allowing the fresh brother to take the injured one's place. Needless to say, such a flagrant violation of the rules is a classic Heel tactic.

Nothing to do with the Twin Threesome Fantasy.

Professional Wrestling

 * The Harris Brothers, in their various guises (The Blu Brothers, Disciples of Apocalypse, et. al.), loved to do this.
 * As did the Shane Twins (a.k.a. The Gymini, or infamously in TNA, The Johnsons [don't ask]).
 * The Basham Brothers are a famed practitioner of the Tag Team Twin trick as well, despite the fact that they're not even related (just have similar builds and bald heads).
 * Mercilessly parodied by The Dudley Boyz when they were on WWE SmackDown!, as Corrupt Corporate Executive Paul Heyman claimed, at length, that he couldn't tell them apart at all, and thus they got away with switching at will. For the record, one of them is white and the other is black.
 * The masked tag team The Killer Bees made this such an integral part of their act that, when they had a Heel Face Turn and took off their masks, they still kept doing this trick, as the Bee on the outside would quickly put his mask on and take his partner's place. This is kind of ridiculous if you think about it; we all know pro wrestling referees aren't the sharpest knives in the drawer, but you'd think a ref would notice that the guy suddenly has a mask on when "he" didn't before...
 * It made perfect sense - inasmuch as anything does in wrestling - because BOTH guys would put on their masks, so the ref had no idea who the one being beaten on seconds earlier was.
 * However, for whatever reason, when Koko B. Ware tried the trick while teaming with the Bees, the ref caught on. Don't know how that could have happened....
 * Billy and Benny Mc Crary were Tag-Team Twins, as well as the world's heaviest twins.
 * The Haas Brothers Charlie and Russ could pull this off. Unfortunately Russ died before making it to the WWE.
 * Subverted: The Briscoe Brothers are neither Briscoes (the legal name is Pugh) nor twins (Jay was born a year and a week before Mark), but they are real brothers. They pulled the twin-switch a few times earlier in their careers, though - however, since then, they have gotten extensive tattoos that make it easier to tell one from the other (with Mark Briscoe's missing front teeth giving away the difference pretty handily). After all, it's hard to mistake Jay for Mark when he has "Jay" tattooed on his arm...
 * WWE Smackdown!'s Brie and Nikki Bella often employed this trope early in their tenure, when Brie was a singles wrestler and Nikki was yet to be revealed. They eventually got exposed by Victoria and Natalya, and then began wrestling as a tag team, still doing the switch on occasion.
 * Subverted by the Uso Brothers. Despite being twins, pointing out the fact most people couldn't even tell them apart and being rudos, they refused to fall back on this trick. Then they tried playing it straight after a losing streak on WWE Superstars.
 * The Body Donnas (who, like the Bashams, weren't really related but used similar hair styles, builds and identical costumes to play twins) did this on a regular basis during their WWE (then WWF) run, but had it backfire when one of the brothers was booked in a singles match against Ahmed Johnson. Despite the twins switching behind the ref's back, Johnson simply picked up where he left off and continued to beat down whichever twin was in the ring. Then the ref caught them trying to swap again and chased the legal twin out; he turned back just in time for Johnson to hit his finisher and get a three-count on the "wrong" man.
 * Inverted when face team The Headbangers, while not identical, looked similar enough to use this trick to steal a win from heels Marc Mero and Golddust.
 * The Quebecers tried this once. The obviously fatter Pierre was quickly called out on it by the referee, despite scrunching himself down as small as possible to look more like Jacques.

Anime and Manga

 * The Kongo twins of Eyeshield 21.

Video Games, Visual Novels

 * Ingo and Emmet the Subway Bosses from Pokémon Black and White
 * Mion and Shion in Higurashi no Naku Koro ni during the game segments.
 * Hisui and Kohaku from Tsukihime can fight as a tag-team in the fighting game spinoff Melty Blood.
 * Kirara and Sarara fights as a team in the Story mode of Magical Battle Arena, and even their opponents will comment that their being twins made them formidable opponents after the battle.
 * from Yggdra Union use similar tactics on a larger scale, retreating when one is about to be beaten and letting the other attack shortly afterwards - and until they're both on the same battlefield, the game displays both of their names as . However, there's enough differentiation between them that a sharp-eyed player can tell them apart.

Live Action TV

 * In an episode of NCIS, the team figures out how a serial murderer committed their crime with an alibi to back them up.
 * On Xena Warrior Princess a wrestling show solves the problem of the twin switch by making twin teams compete in tornado matches instead of tag matches.

Webcomics

 * Used against the York Sisters in Rival Angels. Damage Inc. beat up one of the twins outside the ring, and then roll her in while the referee's distracted for an easy pin.

Film

 * In, the main character goes to great lengths, so far as violating the laws of physics,.