Watery Double

This spell may be cast on any body of liquid as large as an ocean or as small as a glass of wine. The first creature whose reflection is cast on the surface of the liquid releases the spell. When the spell is triggered, the liquid immediately forms an exact three-dimensional image of the reflected creature. If more than one creature casts a reflection simultaneously, only one watery double forms. Each creature has an equal chance of being the victim of the spell (roll randomly).
The size of the watery double is restricted by the volume of fluid available. If the spell were cast on a full mug of ale, the double would form from the ale, becoming a mug-sized duplicate of the victim. The watery double will never exceed the actual size of the victim regardless of the size of the body of liquid.
When the spell is cast on the liquid, its duration is considered permanent until the power is released by a creature's reflection. The liquid will not evaporate until the spell is triggered. When the watery double forms, it remains animated for 1 round per experience level of the caster, to a maximum of 10 rounds.
The watery double attempts to touch the creature it has duplicated. It can affect only the creature that it resembles. It has the same THACO and current hit points as the creature it duplicates, but cannot cast spells or use any of the creature's magical items or special abilities. The watery double is AC 6 and its movement rate is double that of the victim. It may seep under doors and through cracks.
If the watery double succeeds in touching the creature, it merges with the individual, covering his entire body in a skin of liquid. The victim must attempt a saving throw. If successful, the creature has resisted the spell's effect and the watery double "dies," becoming normal fluid (and soaking the creature in the process). If the saving throw is failed, the watery double begins forcing its way into the victim's body, inflicting 1d8 points of damage per round until it is destroyed.
The watery double dissipates if reduced to zero hit points or when the spell's duration expires. Striking the watery double while it is wrapped around its victim causes an equal amount of damage to the victim. Part water, lower water, and transmute water to dust spells instantly destroy a watery double.

[Tome of Magic]

School: Conjuration/Summoning, Enchantment/Charm
Level: 3
Rarity: Uncommon

Range: Touch
Components: V, S
Duration: Special; max. 10 rounds
Casting Time: 3
Area of Effect: One body of liquid
Saving Throw: Negates