Devil Monkeys are a subtype of the Bigfoot and one of many primate cryptids from North American folklore, though variants of them exist all across the world - they are notable for being far more aggressive, malicious and feral than the usually peaceful Bigfoot of North America and are said to resemble baboons or other tailed primates, rather than the more bipedal form taken by Bigfoot.
Devil Monkeys are said to have horrible screaming sounds and wild behavior, attacking people on sight and causing widespread panic - this makes them an entirely different beast from most other primate cryptids in that they seem to actively seek out humans and are considered a major threat if encountered.
They may sport more unusual traits such as glowing red eyes, abnormal size, incredible strength, speed and even ghostly traits such as causing mist or shadow to manifest wherever they go but for the most part they are seen as a kind of vicious "wild man" rather than a truly supernatural entity.
Due to the wild appearance, the heightened aggression and loud noises skeptics believe that most Devil Monkeys are simply escaped baboons or similar monkey species that have managed to breed in the wild, much as some big cats have reportedly done in other areas of the world (giving rise to tales of Alien Big Cats).
More fanciful tales see the Devil Monkeys as extra-dimensional visitors, evil spirits, aliens or an aggressive cousin of the Bigfoot, which would make them North America's version of the Yeti.