The warded creature is immune to the effects of one specified spell for every four levels you have. The spells must be of 4th
level or lower. The warded creature effectively has unbeatable
spell resistance regarding the specified spell or spells. Naturally, such immunity doesn't protect a creature from spells for which
spell resistance doesn't apply.
Spell immunity protects against spells, spell-like effects of magic items, and innate spell-like abilities of creatures. It does not protect against supernatural or extraordinary abilities, such as breath
weapons or gaze attacks. Only a particular spell can be protected against, not a school of spells or a group of spells that are similar in effect.