The gelatinous cube's origin is also mysterious. No evidence of any sort of gestation has been found; it has been suggested that the creature accumulates over time from dead gelitinous material gathering in oubliette-formations beneath very large subterranean dungeons. However it happens, once alive the creature moves constantly, ascending or descending though chimneys and roaming along passages in search of both dead and alive victims. Since the creature can move through a slot only an inch high and a foot wide, it is clear the cubic shape can be suspended and regularly is.
Despite its appearance, the cube should not be mistaken for a solid mass; its thick, green-tinted clear color 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 - far too heavy to be physically restrained; the cube has been known to simply push in doors.
Indigestible objects may be swept up by the cube as it moves and remain inside for several weeks before they are expurgated. These tend to be bits of metal, glass and hardwoods; the creature is able to digest wood but as such sinks inside the creature a large, thick piece may be deposited instead. Flesh is usually digested within an hour; bone may take up to three to four days.
When attacking, the gelatinous cube will typically advance two hexes and produce a length of protoplasm, which it uses to strike living victims. Apart from damage done, a saving throw against paralyzation must be made; failure indicates the victim will be paralyzed for 5-20 rounds. Because of its size, others will not be able to keep the cube from moving over the victim; thereafter, the victim has the potential to die within 3-12 rounds. The only possible remedy will be to kill the cube and extricate the victim (which will take two full rounds) before the enzymes in the cube will cause the paralyzed victim to fall into shock and die. There is no save from this death except to succeed in the original save against paralyzation.
The cube may consume up to nine victims at once ~ but it will not attempt to consume victims more quickly than one every three rounds.
The cube has many powerful immunities. It cannot be stun-locked. Sharp-edged or stabbing weapons will only cause half damage, though bludgeoning weapons are effective. It is immune to magical and natural lightning, and cannot be paralyzed, held or polymorphed. Because it is non-intelligent, it cannot be affected by any form of charm. Cold-based attacks will slow the creature for 2-5 rounds, so that it moves half-speed and attacks every other round.