Familiar Subtype (3.5e Feat)
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Familiar Subtype [General]
Any new familiars gained by the spellcaster have the option of gaining a subtype.
Prerequisite: Knowledge (Arcana) 8 ranks, Spellcraft 8 ranks, Improved Familiar
Benefit: Upon gaining a new familiar, you may imbue it with either an elemental subtype or an aligned one (Fire, Water, Earth, Air, Celestial, Fiendish). This grants it Resistance %25 towards fire if the fire subtype, gives it Burrowing Speed 30ft for an Earth type, Swim speed 30ft (And a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. Also can use the run action while swimming, provided it swims in a straight line)for the water subtype, and Fly speed 30ft (average) if of the Air subtype. If fiendinsh or celestial, any natural weapons posessed by the familiar are treated as good-aligned (If Celestial) or evil-aligned (If Fiendish). The familiar's Alignment changes to match its subtype.
Normal: A familiar's type changes to magical beast. No other effects gained at first level
Special: Not all that useful unless you come across a lot of foes with the same resistances, or if you are travelling to a particular plane.