Giant centipedes are loathsome, crawling arthropods that arouse almost universal disgust from all intelligent creatures (even other monsters). They are endemic to most regions.

One of the things that makes the centipede so repulsive is its resemblance to the worm. Its long body is divided into many segments from which protrude many tiny feet. Hence the name "centipede" (or hundred-footed). The giant centipede is so named because it is over 1-foot long. The body is plated with a chitinous shell and it moves with a slight undulating motion. The creature has the added benefit of protective coloration, and varies in color depending on the terrain it inhabits. Those that favor rocky areas are gray, those that live underground are black, while centipedes of the forest are brown or red.

Combat: When hunting, centipedes use their natural coloration to remain unseen until they can drop on their prey from above or crawl out of hiding in pursuit of food. They attack by biting their foes and injecting a paralytic poison. The poison can paralyze a victim for 15 minutes. Due to its small size, the giant centipede is less likely to resist attacks. Although a single giant centipede rarely constitutes a serious threat to a man, these creatures frequently travel in groups. When more than one centipede is encountered, the monsters will fight independently, even to the point of fighting among themselves over fallen victims.

Habitat/Society: The centipede behaves like most other insects, roving from place to place in search of food; it has no set territory or dwelling. The centipede simply goes where its hunger leads it. It is an aggressive and hungry carnivore that must eat at least once a day to survive. Hungry centipedes often resort to cannibalism.

Ecology: Giant centipedes have several natural advantages, including poison and protective coloration, allowing them to compete with other small predators for game. Their poison bestows a certain immunity from being hunted, but hungry and skilled animals such as coyotes and large predatory birds hunt them effectively in lean times.

Their preferred targets are small mammals that are easily overcome by their weak poison. If they are very hungry, however, they have been known to attack anything that moves, including humans.

These are identical to giant centipedes save that they are only 6 inches long. Their poison is weaker than that of their larger cousins. Mice and other large insects are the favorite prey of huge centipedes. They in turn are hunted by giant centipedes.

The megalo-centipede, because of its great size, is no longer classed as an irritant but is a threat to human and animal alike. Its acidic poison is far more potent than that of its weaker cousins. The victims of a megalo-centipede bite receive acid burns from the poison as well as possible death from the paralysis of heart and lungs if not treated promptly.

The megalo-centipede is more intelligent than its smaller cousins and it is a far more cunning hunter, although they still do not cooperate with each other. In the wilderness the megalo-centipede prey on animals the size of deer. In the subterranean environment, it attacks man-sized or smaller creatures, including orcs, goblins, or humans.

This cousin of the giant centipede feeds upon and lays its eggs in carrion. A tunnel worm attacks by lunging out of its hidden burrow to strike. Success indicates the tunnel worm has seized its prey in its mandibles. Tunnel worm lairs often have treasure from earlier victims.