"A legendary snake said to reside throughout Japan, though some claim to have spotted it in the Tselinoyarsk region of the Soviet Union and within the Central Africa area of operations. Has a body as fat as a beer bottle, but a very slim tail, and is said to move like an inchworm rather than slithering in a snaking motion. Since there are no official records of its capture, it is eagerly sought after by UMA enthusiasts."
―Tsuchinoko description in Metal Gear Solid V: The Phantom Pain

The fabled Tsuchinoko, sought after by the Unidentified Mysterious Animal Club.

The Tsuchinoko (ツチノコ, Tsuchinoko), is a legendary snake-like cryptid from Japan. The name tsuchinoko is prevalent in Western Japan, including Kansai and Shikoku; the creature is known as bachi hebi in Northeastern Japan.

Tsuchinoko are described as being between 30 and 80 centimeters in length, similar in appearance to a snake, but with a central girth that is much wider than its head or tail, and as having fangs and venom similar to that of a viper. Some accounts also describe the tsuchinoko as being able to jump up to a meter in distance followed immediately by a second jump while still in the air.

According to legend, some tsuchinoko have the ability to speak and a propensity for lying, as well as a taste for alcohol. Legend also records that it will sometimes swallow its own tail so that it can roll like a hoop. They are said to be delicious. EVA has eaten one herself, having been served it alongside shark fin soup. When shot they will emit a squeaking noise much like a rat.

Metal Gear Solid 3: Snake Eater

In Metal Gear Solid 3: Snake Eater, the Tsuchinoko is an rare snake that is undetectable by radar and thermal goggles. It can be caught by placing mousetraps around the area, or it can be killed by use of weaponry. When eaten, they fully replenish Naked Snake's stamina. If the player contacts Para-Medic after capturing it, she (as well as the others) will congratulate Snake, who is completely clueless to what the big deal is, then Major Zero will order him not to eat the Tsuchinoko under any circumstances, much to Snake's disappointment. If the player finishes Metal Gear Solid 3 with the Tsuchinoko still with him, they will be awarded the rank "Tsuchinoko" and be given the Infinity Face Paint which will give Snake infinite ammo when worn. If the player manages to capture a "Tsuchinoko" in the Metal Gear Solid: HD Collection, they will be awarded with an trophy/achievement called "Believe It or Not," a reference to the bizarre events investigating group called Ripley's Believe It or Not!

Metal Gear Solid: Portable Ops

In Metal Gear Solid: Portable Ops, if Naked Snake does not set off any alerts, his codename will be "Tsuchinoko," If the player beat Portable Ops Plus on any difficulty without setting off alert mode, they will get a feather for their picture and Tsuchinoko for their codename.

Metal Gear Solid V: The Phantom Pain

In Metal Gear Solid V: The Phantom Pain, Tsuchinoko can be caught using a trap in the northern parts of the Lufwa Valley. If the player captures it, Ocelot remarks that nobody has ever caught one before and says that Snake made the discovery of the century.

Tips for catching a Tsuchinoko

In HD Collection, there is a trophy/achievement to be gained from catching a Tsuchinoko called "Believe it or Not." There are several places in the game to catch one which are explained here:

The easiest way to catch Tsuchinoko is to go through either Graniny Gorki South (after defeating The Fear) or in Sokrovenno (after defeating The End) killing all of the animals in the area, locating them using the sonar. Once all of the other animals are gone, the Sonar will still show something. Go to the exact spot and lay several mousetraps right on it. Leave the area (if the player is in Sokrovenno North, go to the south or west area, etc.) and they should hear the trap spring when they re-enter. Another way is in Graniny Gorki South, there is a tree that has a flat top. It is a little bit south of the center of Graniny Gorki South, in front of the tree is some tall grass, place a lot of mousetraps, (the more the better) run around for a while and you should eventually catch the Tsuchinoko.

Another way to catch it would be by going into the area with the electric fences in Bolshaya Past South, after the encounter with the Ocelot's at the Rassvet abandoned factory by going into the grassy area near the Desert Facepaint in the tree trunk. Place mousetraps in that area where the guard is patrolling and wait a couple minutes and the player should soon have it. Or in that same area go to the bottom right and in front of the fence place a couple of Mousetraps in front of the Kerotan at the bottom of the tree to catch it faster. To get a mousetrap in that area go to the area ahead with the Helicopter and check in the little wooden cabin and get the mousetrap. Then head back and use the mousetrap for the capture of the Tsuchinoko. The player can also catch it with comparative ease at the northern end of Sokrovenno West on the right hand side of the river, three or four mousetraps will be enough.

Also after the player is captured by Colonel Volgin, they will lose all of their items and food. After meeting up with EVA behind the waterfall, go back the way you came and the Tsuchinoko will be in this area, near a log. Simply use the MK22 to capture it alive. The player can also catch it with the Cig Gas Spray before they enter the waterfall. The player won't need to use any mousetraps, as it will be clearly visible. The player will only be able to capture this Tsuchinoko if they caught one in one of the aforementioned areas. EVA returns the player's weapons, but not food, so this Tsuchinoko is simply the one the player had captured.

The fastest method for catching a Tsuchinoko is to shake down Ocelot in Rassvet for a mousetrap during the Virtuous Mission and set it before following after Sokolov, retrieving it when returning during Operation Snake Eater. Then proceed to Bolshaya Past South and on the east side just before the cliff up to the right, there's a small section of land between two sections of mulch with a tree. Place the mouse trap(s) there and walk away, or go up the edge to the end and wait till you hear the mouse trap go off. You may have to repeat this a couple of times but it shouldn't take more than 10 minutes to catch a Tsuchinoko.

Behind the scenes

The Tsuchinoko was constantly searched after by the UMA Club, which was founded by Major Zero.

The Tsuchinoko also makes an appearance in another game by KonamiCastlevania: Aria of Sorrow.

Naked and Venom Snake are the only ones who have caught a Tsuchinoko.

Tsuchinoko don't have a noticeable taste to Naked Snake if he eats one.