Speed Echoes

One common way of portraying a character as moving very, very quickly in fiction is to make multiple images of them viewable at once. They appear to be moving so fast that they're in several places at once. For the sake of preventing confusion, usually the "non-static" parts are shaded with less color, so we're sure that a character is moving really fast as opposed to being a monster with eight arms. Indeed, this trope is much easier to show than it is to describe—it's one of those effects that usually has to be pointed out to a casual viewer for them to even realize it's there.

In some fiction, the echoes are more than just a special effect—they're literal. Other characters can see them and be confused by them, making them effective covers for highly elaborate martial arts attacks. In video games, they can be used as an excuse to force the player to use timing to hit the "real" image. For various reasons, using Speed Echoes for the Doppelganger Spin doesn't really make a whole heck of a lot of sense, but eh, roll with it.

Note that sometimes this trope can be used somewhat lazily: a character will have Speed Echoes but aren't really moving all that fast. The echoes are just to make us think they're moving fast.

This is somewhat distinct from Doppelganger Attack, although technically a work can employ both at once. Related to Speed Stripes and Flash Step, both of which often employ this trope in their basic function. Indeed, you can see examples of Speed Echoes in action in both of those pages' images.

Anime & Manga

 * Used straight in Ranma ½ to show particularly fast opponents.
 * Memorably subverted in at least one instance. Kodachi appears to do this in the middle of her gymnastics-themed battle with Ranma, but it is quickly revealed that she's actually attacking him with 20 objects at once.
 * In Cyborg 009, one guy who was The Minnesota Fats to the main character could move so fast he did this. Furthermore, the afterimages stuck around for quite a while, effectively being used as a Doppelganger Spin.
 * The first time we see Ichigo from Bleach use his Bankai, the resulting speed increase is so great that Byakuya, who was previously shown as a speed demon, could only see afterimages (when his eyes didn't fail to keep track of Ichigo altogether).
 * This is also the main schtick of the Arrancar Zommari Leroux, at least his pre-Ressurecion form
 * Phantom Miria from Claymore moves so fast, she leaves afterimages of herself behind, greatly confusing her enemies. They think they struck her, then her "body" promptly dissipates and she's already behind them, ready to strike.
 * Several characters of Hunter X Hunter (Kirua and Feitan, notably) do this purposely: the multiple images are visible to everybody, and the characters hide among those in order to proceed with a surprise attack.
 * One of the Tournament Arcs of Dragonball Z had a character pull this trick with a total of eight copies.
 * In Chrono Crusade, Speed Echoes are used to show how fast Joshua can move. Interestingly, there's also another page in the same chapter for an almost theatrical slow motion effect. (Warning: the second page contains a spoiler.)
 * Used by Signum during her first battle with Fate in Magical Girl Lyrical Nanoha A's. "You have pretty good senses for a mage... but when challenging a Belka-type knight, it's not enough!"
 * This is one of Shinomori Aoshi's special attack in Rurouni Kenshin, Ryusui no Ugoki. Its weakness is while the flow of afterimages itself is seemingly unbreakable, the transition towards an offensive move (as is the case with the Jissen Kenbu combo attack) can be anticipated by a skilled opponent (like Kenshin and Okina).
 * Gundam has this for some suits in various series. Often occurs when the Gundam enables a Super Mode.

Comic Books

 * Frequently used in comics to display either superhuman speed or acrobatics. Spider-Man and Nightwing are the undisputed masters of the latter effect.
 * The Flash and his fellow speedsters.

Live Action TV

 * In one of the Dune series, this effect was used to show the preternatural speed Paul had earned through his martial training.
 * A variation is found in The Picard Maneuver of Star Trek: The Next Generation. The premise is that making a short warp jump allows a ship to overtake their own image traveling toward the observer and thus appear in two places at once. Too bad this is completely ridiculous at least for Star Trek. If starships didn't have filters to prevent this, they'd be surrounded by ghost images of every ship that ever entered or left warp in that area, as proven by Lawrence Krauss.
 * The Hand Wave is that although long-range sensors are faster than light, targeting sensors are limited to lightspeed. This fails to explain why they don't use FTL sensors for targeting, but that can probably be handwaved too.
 * In Heroes, when Hiro stops time, he sees a long Daphne-colored trail leading him to the speedster.
 * This effect was used with Vicki in the Small Wonder episode "My Robot Family".
 * Suggested by Raj as a solution when all four of the main characters showed up for a costume party dressed as The Flash on The Big Bang Theory.

Films

 * The Matrix has several examples of this, beginning with the "Hit me. If you can." dojo fight, through the agent in the rooftop firefight dodging bullets, to the "fist bouquet" effect as Smith pummels Neo.
 * Used for the Big Bad in The Chronicles of Riddick, although in his case it's more a matter of slipping through hyperspace (the "underverse") than super-speed.
 * Used to unintentionally hilarious effect in Queen of the Damned. Vampires' unnatural speed is represented by a smeary trail of afterimages... even if the vampire otherwise appears to be moving at the same speed as nearby non-vampires.
 * Final Fantasy VII: Advent Children does this with Cloud's Omnislash version 5.
 * Loz too.

Video Games

 * Very obvious in Viewtiful Joe. To an outside observer, this could just as easily be a magic spell Joe casts which causes a bazillion Joes to appear on the screen beating the bejeezers out of everyone.
 * Many, many, many 2D Fighting Games have the character summon "afterimages" during Desperation Attacks, high jumps, or even evades.
 * Castlevania: Symphony of the Night used afterimages whenever...well...ANYTHING happened, really.
 * This is how the Speed Booster power-up is animated in the 2D Metroid games where it appears.
 * Likewise when the similar power-up appears in the Mega Man X, Zero and ZX games.
 * Sonic the Hedgehog and friends show this in the 2D games, mainly the Sonic Advance Trilogy and Sonic Rush Series.
 * First seen when Sonic became Hyper Sonic in Sonic 3 & Knuckles.
 * Employed by Hotsuma in the PS2 version of Sega's Shinobi
 * In the Super Smash Bros. games, Fox and Falco's Side B moves leave Speed Echoes behind as they zip across the screen.
 * High-end Dual Pistols attacks in City of Heroes create Speed Echoes as the character spins to bring their guns to bear on targets.

Western Animation

 * In Code Lyoko, Ulrich running at Super Speed leaves a yellow trail behind him. His "Triangulate" power relies on Speed Echoes, combining the Super Sprint with Doppelganger Attack. In the real world, the XANAfied people and Polymorphic Specters also leave such an after-effect when moving fast.
 * Played for laughs in one episode of The Simpsons when Homer dashes off and a Homer-shaped dust cloud stays in place for several seconds after he's gone.
 * A similar situation to the Simpsons example above occurs in an episode of Phineas and Ferb. Doofenshmirtz decides to make a quick exit, and a Doofenshmirtz-shaped dust cloud appears along with a *RUN AWAY* sound effect. However, when the smoke clears, a confused Doofenschmirtz is still there, wondering what exactly just happened.