Speedrunners have long been exploiting 8-bit games by "reprogramming" them. Pixel-perfect inputs can be used to trigger memory events, usually for the purpose of beating games in fractions of the time it would ordinarily take. A similar exploit exists in the classic Mario Game Boy game 6 Golden Coins, but it exists in a physical, semi-playable form. Welcome to glitch hell. By falling through the map in a particular stage, speedrunner Chris Grant is able to interact with the game's memory and make it think it's been beaten the next time he enters a new level. Apparently, 6 Golden Coins stored all the data for the cartridge underneath levels (where players were never intended to go) as blocks, pipes and other broken but familiar in-game objects. Touching some of these objects causes a hard reset or renders the entire cartridge unusable. But one block in particular tells the software to load the end-game sequence, which in glitch speedruns, counts as beating the game.
There must be some reason why the 6 Golden Coins programmers found storing memory this way more efficient, but I'm not aware of other Mario games doing anything similar. The bonus is that tinkering around "inside" a game looks a lot like a bad early '90s plot device, a la hacking the gibson. Don't go dusting off your old Game Boy though: The glitch only works on older versions of the cartridge.