Did I just imagine this rule?

[Zaq]

I thought there was a rule somewhere (perhaps even a sidebar or a variant, but a printed rule nonetheless) that either a familiar or an animal companion or both would shun/abandon their master if their master started out as living but became undead. That said, I can’t find said rule anywhere, and I’m starting to think I either imagined it or I’m conflating some unrelated rules into something incongruous. Maybe it was 3.0? I don’t know.

Does anyone know where this odd scrap of half-remembered rule originated (or if I just imagined the whole thing)?

[PrismCat21]

I recall the same rule, but I can't remember where it was from.

However, I do remember a part of the Emancipated Spawn Prestige class in Savage Species if that helps

Recall Class Features (Ex): At 2nd level, an emancipated spawn remembers more of her former existence. ... If the character had a familiar, the empathic link between her and the familiar is reestablished.

[Buufreak]

It's less a hard undead rule, as I've only found it in the vampire entry.

[Zaq]

It's less a hard undead rule, as I've only found it in the vampire entry.

That seems to be what I was semi-remembering! It didn't occur to me to check individual undead entries. I'm glad that I didn't just dream up the entire thing out of whole cloth. Thank you!

[VisitingDaGulag]

I think it was generalized in 3.0

Getting out of the grey area involves making your familiar undead too.

[atemu1234]

I think it was generalized in 3.0

Getting out of the grey area involves making your familiar undead too.

Mr. Tibbles now desires the blood of the living. And boxes. Many boxes.