Undead Companion Feat 5
Source Pathfinder Lost Omens: Ancestry Guide
Prerequisites an animal companion or familiar
Your companion is also touched by undeath, a mix of a traditional companion and a skeleton, zombie, or stranger form of unlife. Your companion gains the undead trait instead of the animal trait and gains negative healing. It otherwise uses the normal rules for an animal companion or familiar; that means it can still be affected by many conditions or effects to which most undead are immune.
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.
DhampirA creature with this trait is a member of the dhampir ancestry. These humanoids are the mortal offspring of vampires and members of other ancestries.