Warning: This is 3.0 Edition material. It is possible that there is more recent 3.5 Edition version.

Darsson's Potion

(Magic of Faerun)

Level: Knight of the Weave 3, Sorcerer 4, Wizard 4,
Components: V, S,
Casting Time: 1 full round
Range: Touch
Target: Flask of water touched
Duration: 1 hour/level
Saving Throw: Will negates (object)
Spell Resistance: Yes (object)

You transform the water in a flask so that it is capable of storing a spell in the manner of a potion.
On your next turn, you or another spellcaster can cast a
spell into the water, transforming the water into a potion of the appropriate type.
Only spells suitable for making potions can be used this way.
The person casting the spell to be stored must spend XP as if a potion were being created with the Brew Potion feat.