The Tsuchinoko is a legendary type snake, from Japan that many have supposedly seen, but only one person has admitted to catching (he let it go however before researchers could identify it, claiming that it was extremely unlucky to have it in his possession)
In Tactical Espionage Action; Metal Gear Solid 3: Snake Eater There is also a elusive snake called the Tsuchinoko. It is invisible on the screen and none of the devices (i.e. motion detector, AP sensor, thermo goggles, night vision goggles, ect.) can detect it, except the sonar. No one even knew about it until rumors from Japan surfaced. Then some people started catching them, even in North America, and Europe.
Para-Medic (the medical/food expert) in MGS3 describes the Tsuchinoko as having intense eyes, can stand-up on it's tail, and able to make noises such as snoring and crying. (Hence my crappy user pic for this entry :P )
So after constantly radioing the medical/surrounding food expert in MGS3, I got "...There is supposed to be a Tsuchinoko in that area..." And so I went out and started hunting with my sonar, directional mic, and mousetraps (the mousetraps in this game are just live traps that can be set and left for something to get caught in). After searching the surrounding areas I came across a hint on a site about the area they were known to be in. I concentrated my search there and *wooosh* caught the snake!