Sudden Aegis

(The Forge of War, page 117, DnD 3.5)

Abjuration

Level: ; Sorcerer/Wizard 3
Components: V, S
Casting Time: 1 immediate action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One creature
Duration: 1 round
Saving Throw: Will negates (harmless)
Spell Resistance: Yes (harmless)

You instantly but briefly grant the subject damage reduction 10/adamantine.