
Absynthyne |

For those who cannot look it up, here is a copy from Plot and Poison (if that is indeed the feat you were referring to).
Absorb Familiar (General)
You absorb your familiar into your body, giving you greater power.
Prerequisite: Must have a familiar.
Benefit: Your familiar becomes a part of you, totally subsumed into your being. Any numerical special benefit your familiar grants you (such as the +2 bonus on Move Silently checks from a cat familiar) is doubled. These benefits become permanent extraordinary abilities. You lose access to all the familiar's other abilities, and you may never again take a familiar. If your familiar does not grant you a numerical bonus, this feat grants no benefits.
This feat may be chosen as a wizard bonus feat.
And a link to Item Familiar.