PFSRD:Improved Share Spells
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You can share spells with those you have a magical connection with.
Prerequisites: Spellcraft 10 ranks, ability to acquire an animal companion, eidolon, familiar, or special mount.
Benefit: Any non-instantaneous spell (but not any spell-like ability) you cast on yourself can also affect a creature bonded to you (such as an animal companion, eidolon, familiar, or special mount). The creature must be within 5 feet of you at the time of casting to receive the benefit. The spell's duration is halved between you and your bonded creature (for example, a spell with a duration of 1 hour has a duration of 30 minutes for both you and your bonded creature).
If the spell or effect has a duration other than instantaneous, it stops affecting the creature if it moves farther than 5 feet away from you. It does not affect the creature again if it returns before the duration expires.
You may share spells in this fashion even if the spells normally do not affect creatures of that type.
This feat only applies to animal companions, eidolons, familiars, or special mounts gained through a class feature.