Two years ago, the "impossible coin" in "Super Mario 64" was collected by YouTuber pannenkoek2012. And just this year, he discovered another unobtainable coin in the island.
YouTuber pannenkoek2012 was a programming-obsessed Super Mario fan who uploaded a video detailing how the coin is hidden in Tiny Huge Island for almost 20 years, without players aware of it according to Polygon.
There is no doubt he knows "Super Mario" more than anyone else. In fact, he received a memetic status with his "Watch for Rolling Rocks" video which was viewed 1.4 Million time on YouTube.
From what most players know, there is a limitation in the number of coin arrangements that can be spawned including a line of five. But pannenkoek2012 realized that there is a string of four coins that can be found on a slope in Tiny Huge Island. Where is the fifth coin? It was actually hidden underground and the coin is said to spawn when Mario enters the secret location.
When the coin spawns, there is a need to check the floor where the hidden coin is located. Since the missing coin is clipped into the ground, it cannot be taken. There is no other valid ground beneath it. Not to mention, the position is not valid which despawns the coin.
There is also no way to hack the game and teleport to its position. The coin exists for about a single frame but it despawns faster. According to the theory of Buchanan reported in Kotaku, the slope where the coin was placed was originally a direct incline upward.
Perhaps, this could justify the ground that is missing beneath the impossible coin. The geometry of the level was modified without knowing the effect on the coins. As of now, it seemed like there is no way how this coin can be collected. The coin also disappears as soon as it spawns.
