Rites Of Transfiguration Feat 14
Source Pathfinder Advanced Player's Guide
You can adapt your patron's power to transform other creatures into forms more befitting their behavior or your whims. Your familiar learns Baleful Polymorph, even if baleful polymorph isn't on your tradition's spell list.
By spending 10 minutes in communion with your familiar, you can replace one spell of 6th level or higher you've prepared in one of your witch spell slots with a baleful polymorph spell of the same level.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
WitchThis indicates abilities from the witch class.