Vardigg

(From Planescape: Monstrous Compnedium Appendix II - 1994):

The varrdig, or fluid brute, is a grue from the Elemental Plane of Water. A varrdig can appear as a pool of water, a fountain, or as part of a greater body of water, although in the latter case its greenish tinge makes it visible with careful observation. Its natural form is a globular, translucent, jelly-like blob with a fringe of small, clawed legs and pipe-like tubes radiating from its middle. These flexible hoses provide propulsion by jetting water when the creature is in its element. 

Combat: A water grue uses its flexible hoses to attac squirting water twice per round with considerable force up to 6’away (Id4 stunning damage, 1 in 6 chance to blind the victim for 1-4 rounds). Any air-breathing creature reduced to 0 hp by stunning damage is unconscious and the grue can drown it in one round by thrusting a tube into a nostril. In water, the varrdig can jet rapidly to ram a opponent (4d4 damage). It can ram twice per round. 

Water grues are immune to water-based spells such as create water, ice storm, wall of ice, obscurement, airy water, lower water, purify food 8 drink, and water breathing. All such magic within 30‘ of the varrdig is dispelled, even permanent effects. Magical items are not affected. 

Habitat/Society: Varrdigs often travel in packs of three, to assume their fused form if threatened. Varrdig triads seek out and claim territories that they defend from all others. When they (soon) depopulate the area, they move on to fresher waters. 

Ecology: Water grues are scavengers, and they also attack weak, diseased, and elderly creatures. varrdig triads: A trio of varrdigs can fuse into a three-lobed entity that resembles a snowman; this takes 1-3 rounds. The combined creature has hit points equal to the sum of the individuals, THACO 5, and Champion morale. The triad will have 3-6 tubes, each capable of projecting a stream with IO’ range and 1d6 stunning damage. Ramming attack damage increases to 4d6.

(From Complete Arcane - 2004):

This foul creature resembles a loose, frigid mass of tainted water encased in a dripping membrane. Streams and pseudopods of liquid flail away from its shapeless body, while dark malignant eyespots drift across its surface.

Vardiggs (or water grues) are brutish and cruel creatures created from the corruption of elemental water, and they systematically seek out and attack any other being that enters a body of water they have claimed as their own.

Vardiggs are about 4 feet in diameter and weigh about 400 pounds. When they bother to, they can speak Aquan in thick, burbling voices. To determine the type of spell-object inside a vardigg, roll d%: 01-70, resist energy; 71—100, sleet storm.

Combat: Vardiggs usually hide below the surface of a body of water, waiting to attack any who approach.

Water Jet (Sp): As a standard action, a water grue can create a tremendously powerful 30-foot line of water. Any creature in the area of the line takes 2d6 points of damage (Reflex DC 11 negates). A creature failing the saving throw must succeed on a Strength check or a Balance check (DC 5 + damage dealt) or be knocked prone by the force of the blast. This is the equivalent of a 2nd-level spell.

Skills: A water grue has a +8 racial bonus on any Swim checks to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered, and can use the run action while swimming, provided it swims in a straight line.