Tool-assisted speed run
A Tool-Assisted Speedrun or TAS, also known as an emulated run or time attack, is a speed run created using emulators to optimise every last frame. They therefore invariably contain feats that are humanly impossible.
Constructing a TAS is more like animating a movie than playing a videogame, and requires much, much more patience than actual videogaming skill. Both TASs and real-time speed runs require concentration, dedication, planning, and far too much free time, but TASs are not listed on this wiki, and you can think of this as the videogaming equivalent of banning steroids. This wiki is about real play.
The most common way of TASing is using (or most would say abusing) slowdown and savestates. Slowdown is when the game's framerate is slowed down to make it run slower, and savestates are used to save the progress suring a project and you can revert to that point if a mistake is made later.