Arbitrary code injection is fascinating stuff. Intrepid gamers have discovered hidden glitch worlds, turned Mario into Flappy Bird, or performed a standard action so many times it crashes the game. The original Legend of Zelda is susceptible too—as glitch hunter Sockfolder found out—and executing the following instructions skips past the vast majority of the game’s quest.
Source: Gizmodo – A Clever Way to Make The Legend of Zelda Beat Itself