The Back O' Beyond Teleporter is a glitch in Grand Theft Auto: San Andreas.
Description[]
In Back O' Beyond, there is a myth stating that if the player drives through a wall, they will fall and get teleported to a random place. As the player enters the mountain wall in a vehicle, they will drive straight through the wall and drop down into Blue Hell. However, if the player doesn't gain enough speed, the player's vehicle may get stuck in the wall. The player may then spawn in a random location with or without their vehicle. Sometimes, the player may even find themself infinitely falling through Blue Hell in their vehicle. To end this, the player must exit their vehicle and they will spawn in a random location. It is unknown why this happens, but evidence suggests that the wall is only a texture without collision, so the player can drive and then fall through it. It can be difficult to make this glitch work, but the results are astonishing.
A more technical explanation says that the Back O' Beyond Teleporter functions like any other instance of the player falling into Blue Hell. Once the player falls far enough down any location, the game will detect that he is far beyond the limits of the game and will teleport him to the nearest pedestrian path to prevent an infinite freefall. Compared to other places where the player can glitch out of the map, the Back O' Beyond Teleporter has a mythical edge because of its likelihood to teleport the player great distances from the original location. However, this is just because there are no pedestrian paths around it.