The Bayside Portal is a proven myth in Grand Theft Auto: San Andreas.
Description[]
A highly strange spawn glitch can be witnessed when the player approaches the Bayside Tunnel from the west. When the player is close enough for vehicles to start spawning, certain cars may suddenly teleport from the road onto the hill above the tunnel, and quickly disappear due to the draw distance. If the player flies a plane or uses the Jetpack quickly enough, the vehicle will not despawn and will instead continue to drive itself towards the nearest pedestrian pathway on the other end of the tunnel, usually getting destroyed in the process.
The phenomenon only happens as the result of a glitch affecting the pedestrian pathway.
Video Investigation[]