Astral dreadnoughts are terrors of the Astral Plane, hunting the void for the projected bodies of those from the Prime; its main food source, those. 30 feet long, with a thick, armored carapace and jaws that can bite through an arm as easily as a sword through water, these creatures are a force any sensible cutter would stay far away from at all times.
Extremely rare, some bloods believe that there exists only one astral dreadnought at any one time. These creatures prowl the Astral ceaselessly, always hunting for projected bodies on which to feed. Seemingly part of the plane on a deeper level than others, dreadnoughts are fully capable of entirely ignoring the hazards of the plane as they roam, being entirely unaffected by shifting conduits, psychic wind, or other natural phenomena. Lucky for many, the dreadnought tends to ignore those physically on the Astral, as opposed to those projecting, though this isn't necessarily a guarantee of safety. If an astral traveler gets in the way of a dreadnought, it will attack just as rabidly as it would in obtaining its prey.
Tremendous beasts, dreadnoughts are entirely covered with a reddish carapace, with the sole exception of its single eye. Beneath this black eye is a massive maw lined with needle-sharp teeth, capable of tearing through plate or ripping off a limb in a single bite. To either side of the head are two huge arms, each ending with a pincer-claw lined with sharp, serrated edges.
The lower half of the dreadnought resembles a serpent, with a barrel-thick silver cord stretching off into the distance. The existence of this cord leads some to think that the dreadnought is in fact itself projecting from some Prime world, not truly a native of the astral. Others, however, believe it is evidence that the dreadnought is not truly on the Astral, but of it; a projection of the plane itself, reacting to the increasing numbers of mortals passing through where they weren't meant to.
- Planescape MCII, pp. 12-13