To the surprise of others, that strange growth on you is actually your spellcasting companion.
Prerequisites
Aberrant Bloodline, Arcane Lore 3 ranks, arcane caster level 3rd.
Benefit
You grow a Diminutive or Tiny tumor somewhere on your body that serves as your familiar.
As a standard action, you can have the tumor detach itself from your body as a separate creature vaguely resembling a kind of animal suitable for a familiar (bat, cat, and so on) and move about as if it were an independent creature. The tumor can reattach itself to you as a standard action. When attached to you, the tumor has fast healing 5. If a tumor familiar is lost or dies, it can be replaced 1 week later through a specialized procedure that costs 200 gp per spellcaster level. The ritual takes 8 hours to complete.
The tumor has all the abilities of the animal it resembles (for example, a bat-like tumor can fly) and familiar abilities based on your spellcaster level. The tumor acts as the your familiar whether attached or separated (providing a skill bonus, the Alertness feat, and so on).
Special
This feat counts as the Obtain Familiar feat and can be selected in place of that feat. You cannot possess both feats.