Fortify Familiar

(Spell Compendium, page 98, DnD 3.5)

Universal

Level: ; Sorcerer/Wizard 3
Components: V, S
Casting Time: 1 standard action
Range: Touch
Target: Familiar touched
Duration: 1 hour/level
Saving Throw: None
Spell Resistance: Yes (harmless)

You touch your familiar, and you see that the creature seems more robust.

This spell makes your familiar tougher, granting it 2d8 temporary hit points and a +2 enhancement bonus to its natural armor. It also has a 25% chance to avoid extra damage from sneak attacks or critical hits (although such attacks still deal normal damage if successful). Temporary hit points gained in this fashion last for up to 1 hour.