- No disguise skill
- Shapeshifters are allowed as long as they fit the rest of the requirements.
- Stuff they get from classes or other external sources doesn’t count it has to be an ability that every monster of that type has.
- it’s okay if the appearance is only skin deep
- anything that you can find on the srd, archives of nethys, or similar sites is okay including 3pp.
- templates are cool too
- no possession
A few notes
- something like a zombie whose flesh doesn’t rot and doesn’t smell like a zombie as a commenter proposed fits the bill
- vampires do fit my criteria as this is mainly about appearances and who goes looking to see if people have a shadow unless they know there’s a vampire around. But I’m already aware of those and I'm looking for stuff I’m not aware of.
So the question is are there any undead that appear to be alive even if it’s only visually.