|Scientific Name||None (cryptid)|
|Loot|| Sasquatch Heart|
|Voice actor||Joel Garland|
–The last Sasquatch to John Marston.
Sasquatch have been described in reports as large, hairy, ape-like creatures, ranging from 6–10 feet (2–3 m) tall, weighing in excess of 500 pounds (230 kg), and covered in dark brown or dark reddish hair. Alleged witnesses have described large eyes, a pronounced brow ridge, and a large, low-set forehead; the top of the head has been described as rounded and crested, similar to the sagittal crest of the male gorilla. Sasquatch is commonly reported to have a strong, unpleasant smell by those who claim to have encountered it.
In Undead Nightmare, they come in both reddish-brown and dark brown colored fur and have an appearance and characteristics similar to a gorilla. The darker colored ones are assumed to be male (as seen in The Birth of the Conservation Movement), while the reddish brown ones are assumed to be female. They are intelligent and are able to speak English fluently. According to Rockstar's game art and a crazy man in the wilderness, they prey on human infants and are "Extremely dangerous and should not be approached". However, they actually eat mushrooms and berries and have been living in the forests of Tall Trees for over one thousand years according to the "last" sasquatch. Despite their appearance, they are very similar to humans by reactions and feelings.
They are always found in and around Tall Trees, regardless if the player kills the supposed "last" one. The in-game Sasquatch are timid and apt to run from the player if threatened in any way. They claim to have been living in Tall Trees for over a thousand years, but they cannot be found in the normal campaign.
In the stranger mission "Birth of the Conservation Movement", the player is tasked by a man wearing clothing similar to the Expert Hunter Outfit to kill the Sasquatch around Tall Trees. When the last specimen is found, he'll tell a moving story about being the last of his kind and how he wishes to be killed. After the cut scene, the quest is complete. However, the player can choose to leave him be or to end his life. If you choose to kill him, sometimes headshots don't kill instantly. So far, this has only happened with the one that tells the story and wants the player to shoot him. This decision will not affect the storyline or the rest of the game. Whether the player decides to eliminate the final Sasquatch or not, the player will occasionally find Sasquatch within Tall Trees.
- The term "Sasquatch" is an anglicized derivative of the word "Sésquac" which means "wild man" in a Salish Native American language.
- Sasquatch cannot be skinned, but can be looted.
- Other humans seem to take no notice of Sasquatch, as noted with the Doctor random event, either this or they aren't considered a threat to the doctor.
- The Sasquatch are surprisingly easy to kill, as they can be downed with a light shot in the back.
- Zombies will chase and kill a Sasquatch as if it were a human.
- After the Sasquatch sits next to the tree if the player punches him he will act like a normal Sasquatch and run. He will also run away if attacked by a Zombie.
- Sasquatches still appear later in the game, after the "last" six were killed.
- If the player attacks a Sasquatch, it will shout "Please no!", "This is my home!" or "You have ruined this land!"
- It is possible to lasso the Sasquatch, but it cannot be hogtied.
- The sasquatch looks a lot like the sasquatch found in the Patterson-Gimlin film, filmed in 1967.
- The sasquatch is most likely a reference to the myths of Bigfoot in the forests of Grand Theft Auto: San Andreas, another game by Rockstar, due to the fact it and Undead Nightmare both came out on October 26, and the Achievement/Trophy for killing a Sasquatch is named Six Years in the Making. San Andreas was released in 2004, six years before Undead Nightmare. The French version of the achievement/trophy translates as "No need to seek it anymore, CJ" (Plus la peine de chercher, CJ).
- It is possible to find both male and female sasquatch. After killing one, closer inspection occasionally reveals a more feminine facial structure and breasts, similar to that of the Patterson-Gimlin Film. There is also a chance for female sasquatch to have flowers on their heads. The dark brown ones are considered to be male and the reddish brown ones are considered to be female.
- The in-game Sasquatch seems to have unusually long legs. Most sightings report relatively short legs and long arms. The in-game Sasquatch's rear end is also quite noticeable.
- When getting the chance to kill the last sasquatch during the mission, if the player throws a tomahawk at its head, it can survive and follow the player around, but it doesn't attack.
- If the player goes just outside of viewing range of the final Sasquatch, and then immediately turns around and goes back, he will have disappeared.
- If the player looks where the Sasquatch steps, instead of leaving their trademark footprint, they leave a shoe imprint.
- The cheat "Beastmaster" does not work with Sasquatch. They will continue to do whatever they were doing.
- Sasquatch seem to recognize firearms. They will stare at the player and sometimes even run away when a gun is aimed at them.
- While viewing a Sasquatch, they will sometimes crouch and eat berries or run randomly even if there is no visible threat.
- During "Birth of the Conservation Movement", Sasquatch can be found around Cochinay, but when the mission is completed, they are only found around the central area of the Tall Trees.
- The in-game Sasquatch is most likely based on a human NPC because of the way they act in some situations. Occasionally, they will "sink" into the ground up to their kneecaps, being the same height as the player. Other times, they can be seen performing human activities, such as hanging out by a campfire and even smoking a cigarette. This can be seen here.
- When lassoed, sasquatches will fall to the ground, as if dead. They do not struggle or move at all. However, if the player releases it, it will continue with its normal activity.
- It is possible to lasso and drag a Sasquatch as far as Manzanita Post. Locals seem to take no notice even though the Sasquatch Hunter claimed a small girl was eaten there by a Sasquatch.
- In Grand Theft Auto V, there's a mission with a man in a Bigfoot suit whose dialogue is based on that of Undead Nightmare's Sasquatch.
- When attacked by Undead Wolves or Coyotes, Sasquatches will uses the same defensive animation used by NPC: where the canine bites onto the arm but is thrown off.
Hunting and killing a Sasquatch will contribute to the acquisition of the following Trophies/Achievements:
Find and kill a Sasquatch.
Attain 100% Game Completion statistic in Undead Nightmare.