Ever since Grand Theft Auto: San Andreas was released, there have been rumours about supernatural creatures roaming several parts of San Andreas.
Bigfoot is perhaps the most well known myth of San Andreas. The creature is claimed to hide in Back O' Beyond and attacks the player. Bigfoot is confirmed to be fake.
 Ghost Cars
Ghost Cars are another myth, although they have some truth to them. There are cars located in Back O' Beyond that move while there are no drivers behind the wheel, but that is because they are simply rolling down a hill.
The antagonist of The Texas Chainsaw Massacre is not, in fact in-game on top of the Panopiticon.
Because on the appearance of an Area 51 parody, players speculated on UFOs appearing as well. The lights far up in the sky have been named by the programming as 'UFOlights' but they are replicating aeroplanes, not UFOs. there are many ufos on san andreas.
Rockstar, in response to the urban myths, set up a false website in Grand Theft Auto IV on The Liberty Tree, making references to the previous myths in San Andreas, plus ones on Liberty City itself, such as alligators in the sewers, secret cities, and invincible criminals. 
Ratman is claimed to live in the sewers and subway, but there is not much information on Ratman.
 Catapult swings
The only myth to be true, although it's more of a glitch, the special swings catapults a car and Niko into the air for several metres when Niko drives a car into the swings at a special angle.
 Bigfoot again
On the in-game Internet, a user named 'Bigfoot' logs in from San Andreas.