Age Dragon

This spell allows the caster to cause any dragon to temporarily gain or lose one age level per five levels of the caster. For instance, a 14th-level caster could cause a dragon to gain or lose two age levels; a mature adult dragon could be temporarily tranformed into a young adult dragon or into a very old dragon. A dragon's age cannot be reduced below hatchling or increased beyond great wyrm.
Unwilling dragons are allowed a saving throw vs. spells with a -4 penalty to avoid the effect.
A dragon affected by age dragon temporarily acquires the armor class, hit points, spell abilities, combat modifiers, size, and other attributes of his new age level. The dragon retains his memories and personality. At the end of the spell's duration, the dragon returns to his normal age level.
If the dragon suffered damage while experiencing his modified age, these hit points remain lost when he resumes his normal age. If the dragon loses more hit points at his modified age than he has at his actual age, he dies when the spell expires. For example. a young adult bronze dragon with 110 hit points is aged to a mature adult with 120 hit points. The dragon suffers 115 hit points in combat. Unless the dragon is healed of 6 points of damage before the spell expires, the dragon dies at the end of the spell since his damage is greater than his actual hit points.
If a dragon is killed while under the effect of age dragon, he is dead at the end of the spell's duration.

[Tome of Magic]

Sphere: Time
(Alteration)
Level: 7

Range: 30 yards
Components: V, S, M
Duration: 1 round/level
Casting Time: 1 round
Area of Effect: One dragon
Saving Throw: Negates

Material Components:
a handful of dirt taken from a dragon's footprint