Though estimated as wide as 10 feet in size, the gelatinous cube is more accurately estimated at 7 to 8 feet in breadth. Additionally, the cube should not be mistaken for a solid mass; its thick, greenish hide conceals that much of the interior consists of dozens of hollow chambers, which flow like bubbles in the cube's interior. Despite this structure, the gelatinous cube is still considerably massive, typically weighing about eight tons.
Indigestible objects may be swept up by the cube as it moves and remain inside for several weeks before the cube's digestive process completes and the objects are cast out behind the cube. These tend to be objects made of metal, glass (such as potion vials) and stone. Wood or paper objects will be completely digested, leaving no remnant. The cube will usually digest bone entirely, but this takes longer than to digest the surrounding flesh and muscle. The digestive process of the cube is nonetheless gradual, and if little time has passed since the cube absorbed a being or digestible object, it may still be recoverable before the cube breaks it down.
As the cube does not need to rest, it simply continues to scavenge until it runs out of food or is destroyed. The former is highly unlikely, as the gelatinous cube is capable of digesting all forms of organic matter and inevitably will collide with another life form given enough time. When this occurs, the exterior of the cube releases a paralyzing electric shock which stuns for up to 4 minutes (save vs paralyzation, stun for 5-20 rounds) given the organism enough time to surround and digest its victim. Meeting a wandering cube in this way is the only form of encounter possible.
Gelatinous cubes are immune to electricity, fear, holds, paralyzation, polymorph and sleep based attacks. They take only 1-4 points of damage from cold attacks and may be slowed 50%, if they fail their saving throw. Fire and weapons damage the cube normally.
As well, the creature cannot be stunned, for though it can be attacked by normal weapons, no part of the body is made off balance by another part being attacked. This is true of all jellies, slimes and oozes.
Cubes reproduce asexually by budding, in which a stub cube splits off from the parent. The parent cube may digest its own stub if they converge again. Claims that somewhere hidden in the bowels of the earth exists a "mother-cube" from which all others have budded are advanced but utterly nonsensical.