The biggest loser in Zelda: Majora's Mask finally ends its 25-year losing streak, as 30,000 brute-force attempts finally debunk the myth of Blue Dog

gamesradar.com:

The greatest losing streak in the history of the Zelda series has been ended after 25 years thanks to a Majora's Mask fan who provided the perfect conditions for the game's most unfortunate NPC to finally triumph - and it still took 30,000 attempts.

'The Legend of Blue Dog' stems from Majora's Mask's dog racing minigame. In that game, Link can pick a dog to bet on, gaining rewards if his pick does well in the next race. There are 14 dogs to bet on; four white, three gray, three beige, two brown, one gold, and one blue. Each dog's chance of winning isn't a simple one-in-fourteen, however - their color and condition will both affect their performance in the race. 

Every time the dogs are loaded in, they're granted a condition that can augment their speed - essentially, the number of frames that each dog moves every second. Four dogs will get a good condition, increasing their speed a little, while five will get a bad condition, which slows them down. Those conditions build upon the dogs' base speeds, which depend on their color - the gold dog is the fastest, with a base speed of six, while the White and brown dogs are a little slower, with a speed of 5.5. The gray and beige dogs have a speed of five, but the unfortunate blue dog clocks in at 20% slower than that, with a speed of just four.

Blue Dog is so famously slow that he's become something of a legend within the game's community, a literal underdog widely considered to be incapable of winning the race. As explained in a video from Vidya James, there was thought to be just one, extremely rare, means of securing a W for Blue Dog. In the game's code, the race is divided into three zones - the first half of the track, the second half, and the finish line. These three zones intersect in a small area at the line, and if a dog is found to be in all three zones at once, it wins the race.

The problem here is that Nintendo's zone drawing went a little outside the lines, and a single, extremely thin part of the finish line