|Not to be confused with the Cave Monster of the same game.|
The Tunnel Creature is what appears to be a pedestrian figure with a pitch black texture, who is said to inhabit a Train Tunnel located in Flint County, which is located just north of the Leafy Hollow farmstead.
The Tunnel cuts through a hillside entering from the East and winds several hundred feet before exiting on the Northern side of the embankment. The Tunnel itself is one of the darkest places in San Andreas as it has no interior lighting.
Interestingly, the lights on most cars sometimes flicker on and off at certain parts of the cave, especially on motorcycles.
This phenomena was first discovered by a YouTuber. In his first video on the subject, he claims to have captured a figure in one of his in-game camera shots he took during filming. The image's brightness and contrast had to be modified before the figure could be visible. His claim was met with some accusation as viewers believed the image was faked.
A shrieking scream can be heard around the 4:59 minute mark in the video. The sound was extracted from the video, a hard limiter applied and the volume boosted to better hear the audio. The sound-byte was uploaded by a fellow YouTuber.
The Hillbilly Pedestrian
Towards the end of GTAMythHunter's second feature-length video, a Countryside Pedestrian with the model name CWMYHB1 was found wandering inside the Northern entrance to the Tunnel. The Pedestrian was walking, travelling south towards the Western exit of the Tunnel.
When attacked, the pedestrian initially did not respond, but soon threw his arms up to surrender as regular Pedestrians do when threatened with a firearm. Interestingly, the Pedestrian did not seem to take damage, as shown by his full-green health indicator. The YouTuber and his recruited gang member began firing on the pedestrian once more, but this time, the Pedestrian drew a Desert Eagle and began firing back. The Pedestrian still did not indicate to be taking damage, while it focused most of its fire on CJ. The pedestrian was able to be killed after being finished off with an AK-47.
It was most likely a fake, as there are mods to spawn peds in certain places, and some can be assigned to certain keyboard buttons (e.g. Binding F12 to spawn [Ped Name] with [Weapon Name] could have possibly been used.)
It was most likely not a spawn glitch, because if it were, this would happen every time with the Tunnel. For example the coder put it in the wrong coordinates, and instead of putting them in, say a farm, they put them in the Tunnel. Since there are no consistent results and little known causes, this is most likely a fake.
The camera one was also most likely use of a modification, probably to spawn entities, then he put the pedestrian in a dark spot and then claiming he caught something on camera. The pedestrian also could have been photo-shopped in, as he seems to have smoother quality and fewer polygons than normal pedestrians, and seems to have his hands in his pockets, which no animation for the pose can be found in the game files.
Sometimes, trains can be witnessed travelling at exceptionally high speed in and out of the Tunnel. Trains in the area have also been witnessed travelling in the wrong direction for the railway or changing the direction of the railway. Players have theorized these trains are apparitions. However, it is important to note a driver can be seen in all supposed ghost trains.
Birds can also be observed flying both in and out of the tunnel entrances, but the reason is not known to the players.