The Behemoth never harms any living thing and doesn't appear to be hostile in nature, but it is said to be larger than anything that ever lived on Earth. Its lack of hostility could be due to its sheer size - it simply does not notice anything beneath it. Its very size is a hazard and it frightened the survivors into thinking that there was nothing any better ahead of them.
While the escapees from the market are driving the Land Cruiser on an unknown highway through the Mist, the Behemoth moves across the highway directly in front of the Land Cruiser, flattening utility poles beneath its feet.
The creature's exact size is never specified, but it has six massive legs.
The Behemoth's legs have hundreds of Scorpion-Flies attached to them, and slaty-grey skin mottled in places to dark brown, but apart from that, the creature is unseen.
David gets an impression that the Behemoth's size would make a blue whale resemble a trout and also dwarf the largest dinosaur. Its weight is sufficient to leave footprints the size of large SUVs in solid concrete. It seems to be larger than the Film version.
The Behemoth has six double-jointed legs, each about 18 feet tall, hundreds of multiple-jointed appendages on its underside, and tentacles above its head. The Behemoth's size is estimated at over 240 feet, larger than anything that ever lived on earth.
- The Behemoth is by far the largest creature seen in either the novella or the film.
- Originally, the Behemoth was cut from the film adaption, but Frank Darabont was later convinced by the special effects crew to put it back in.
- Some fans believe that the Behemoth is the creature which the Tentacles from Planet X are attached to. However, this is very unlikely, as the Behemoth only has tentacles on its underside and above its head, and even then, these tentacles are not near long enough to grab human victims that are at ground level. That and the people in the supermarket would have heard the creature coming.
- In the film adaption, in place of the hundreds of Scorpion-Flies clinging to its legs in the novella, the Behemoth has a more scattered swarm of small, winged creatures flying around its underside. It is unknown if they are related to Pterobuzzards or not.
- It is possible to suggest that the Behemoth is a Scorpion Fly Queen, due to their similar appearance, both are hexapods, and have a similar body shape, Scorpion Flies are mentioned to cover the massive legs of the Behemoth in the novella, suggesting either a possible Mutalistic relationship or the aforementioned hive lifestyle.