Demon Wall (3.5e Monster)

''The party fighter reaches for the door and pauses. "What's wrong?" you ask, as he turns around with a frown. "It's warm... this isn't good." Suddenly there is a terrible rumble, as the wall seems to engulf the door and a vicious demonic head with two clawed arms tears forth!''

The demon wall is a terrible haunt from Carceri, the prison plane. Without a body, it haunts the walls waiting for unsusspecting victims to pass near, only to entrap them in the room and devour them. Bodies engulfed in the demon wall's ectoplasmic morass which composes its body are sent to Carceri, where escape is all but impossible. Because it takes on the appearance of the surrounding possessed wall, its body appears to be made of wood, stone, and brick, shaped into a terrible demonic head and arms flailing about with hunger.

Combat
The demon wall is simple and straight forward, manifesting suddenly right as its prey is near to it, and attempting to slow the escape of others. It usually starts out with a quickened arcane lock to cut off any escape from the room, then either slows the party or subjects them to the hampering effects of an ice storm, which manifests from the cieling. It will move forward every round, until it engulfs the entire room, striking physically against creatures which seem weak of body and easy to grab and devour.

Engulf (Ex): Although it moves slowly, a demon wall can simply mow down Large or smaller creatures as a move action. It cannot make a claw or bite attack during a round in which it engulfs, though it may use its spell-like abilities. The demon wall merely has to move over the opponents, affecting as many as it can cover (and since it covers the entire wall usually, it's anything that has not moved down its hall). Opponents can make opportunity attacks against the demon wall, but if they do so they are not entitled to a saving throw. Those who do not attempt attacks of opportunity must succeed on a DC 21 Reflex save or be engulfed; on a success, they are pushed back or aside (usually a non-option) as the demon wall moves forward. Engulfed creatures are lost in a slurry of fiendish ectoplasm, and after spending one full round they are plane shifted to Carceri where they are undoubtly imprisoned. While held in the ectoplasmic slime they are considered to be grappled. The save DC is Strength-based.

Spell-like Abilities (Sp): At will- ''Quickened Arcane Lock, Darkness, Ice Storm; 2/day- Confusion, Slow; 1/day- Flesh to Stone.

Stomp (Sp): A demon wall can cause the surroundings to shake and rock as it moves ahead. In a 20ft cone shaped spread, it causes all creatures to make a Reflex save DC 21, or fall prone and take 6d4 nonlethal damage, save negates. It may perform this every 1d4 rounds as a swift action. The save DC is Strength-based.

Durable (Ex): Because of it's inherently tough, constructed body, it gains additional hit points as if a construct. The large demon wall above has an additional 30 hit points due to its size.

Light Sensitivity (Ex): Born in darkness, the demon wall takes additional damage and effects by [Light] spells which deal more damage against certain creatures. In addition, if ever trapped in daylight, it loses its fast healing and can only take one move or one standard action a round as if slowed. For this reason, demon walls only manifest during the night, or underground.

Wallbound (Ex): The Demon Wall has no inherent material body of it's own, rather it chooses to haunt a wall. At rest, a demon wall is almost impossible to detect, though a detect evil spell will pick up the wall itself as being evil. As a free action it can choose to manifest itself, coating the haunted wall in a layer of thick ectoplasm, blocking off any doors or windows the wall may have and allowing it's demonic visage to appear and attack. Until it manifests, it cannot be targeted without demolishing the wall entirely or otherwise exorcizing it. Even when not manifest, it has its tremorsense to let it know when creatures are nearby. It often does this to gain a surprise round. The Demon Wall is connected to its wall, and it's movement is rather a growth of the ectoplasm, usually forced to move straight ahead down whatever hall or room it is in, until it has engulfed everything in the room and touches the opposite side. A wall demon may be haunting a very wide room, wider than 10 ft. across, but unless it is also abnormally tall it should still be considered a large creature only. A demon wall may return to its resting, invisible state as a full-round action.