The official GemStone IV encyclopedia.
An animated slush could easily be mistaken for a huge pile of snow that has partially melted then refrozen. It presents a squat, icy white cone ten feet wide at the base but only rising five feet high. The edges are slightly transparent and tinged a light blue, while the interior is dark, with portions seeming more solid than others. Rippling over the terrain, its exact motion indiscernible, the animated slush unerringly finds its prey, yet it displays no sensory glands of any type.
Animated slushes are the most dangerous of the three inhabitants of Gossamer Valley. In addition to possessing several spells, they have a "slush wall" maneuver which is effectively an ice based Major Elemental Wave that they can use without having to prepare it as a spell. Aside from their Minor Water (903) bolt, all of their spells and the maneuver possess knockdown AND RT inducing capacities. If glacial morphs are present, this can quickly lead to death or heavy injury, as their high AS takes advantage of your now prone state.
Given their liquid-like nature, animated slushes do not take wounds to any part of the body. In addition to this, they are highly resistant to damage, both physical and, to a lesser degree, magical. However, they are highly susceptible to fire based magic and weapon flares. In this respect, it is highly advisable for melee combatants to bring drake or fire flaring weapons when intending to combat slushes. (In fact, any attempt to wound them with a weapon that does not possess fire, steam, or plasma flares will not succeed.) Clerics and empaths would be best served using Fire Spirit (111), bolting Sorcerers can use Web (118) coupled with Fire Spirit (111) and/or golden wands, Pain (711), or batter them down with Mana Disruption (702) and Disintegrate (705). Wizards should use any of their array of fire based spells.
Slushes are not easily disabled or stunned, so unlike many creatures with dangerous maneuvers, there is little that can be done to prevent them from performing them. For example, while a sorcerer could use Corrupt Essence (703) to prevent a slush from performing a Major Elemental Wave, this will not prevent them from using the virtually identical and just as dangerous Slush Wall maneuver.
Like glacial morphs, the Animated Slush does not drop gems, but will drop various amounts of gold dust that is needed to train in Perception to find.