Long story short, this modder built a controller that, when plugged into a Nintendo Entertainment System, auto speedruns Super Mario Bros. in just a shade under 5 minutes. Naturally, commenters have shouted it down as a fake, but the Tool-Assisted Speedrun community is unanimous in calling the mod real.

Modder pjgat09 provides a step-by-step, with a parts list and explanation, for converting an Arduino Duemilanove board into a working auto-controller, including how to fetch and load the code powering the auto-speedrun onto the board. It works off of a "movie" submitted to and approved by TASVideos, which is "a series of recorded button presses that in theory can be played back on the actual console for which they are intended." While in most cases it's not possible to use this series on an emulator playing a game, it is on the original console.

"These button presses are based on frames on the console," writes pigat09. "Almost every time the console redraws the screen (~60 times a second), the controller is polled for input. However, there are times when the screen is redrawn, but the controller is not polled. These are called lag frames." How lag frames are handled is what sets an emulator apart from a console.

Of course, the lay audience rips this to shreds on any number of counts: 1) It starts up too fast. 2) Mario seems to collide with a dozen piranha plants, fireball columns, etc., and even wall-jumps toward the end. The Tool-Assisted Speedrun community is adamant that this uses known and native tricks of the game to finish it out. The modder says he has used the device on Super Mario Bros. 3, also.

NESBot: Arduino Powered Robot beating Super Mario Bros for the NES [Instructables, thanks TestZero.]