Antidragon Aura

(Spell Compendium, page 14, DnD 3.5)

Abjuration

Level: ; Cleric 3; Sorcerer/Wizard 3
Components: V, S, DF
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels
Target: One creature/ 2 levels, no two of which are more than 30 ft. apart
Duration: 1 minute/level
Saving Throw: Will negates (harmless)
Spell Resistance: Yes (harmless)

You unleash the power of this spell and the nugget of platinum vanishes from your palm. Your companions are bathed in a white aura with a silver scale pattern overlaid upon it.

All subjects gain a +2 luck bonus to Armor Class and on saving throws against the attacks, spells, and special attacks (extraordinary, supernatural, and spell-like) of dragons. This bonus increases by 1 for every four caster levels above 5th (to +3 at 9th, +4 at 13th, and a maximum of +5 at 17th).

Material Component: A chunk of platinum worth at least 25 gp (slightly less than 1 ounce).