Q 691

I believe there's a monster in some first party book that is basically an animated face in a door. I can't find it, though, either because it's not in the books I'm checking or because I'm blind or something like that.

The creature looks like a pleasant face in a door, and has an accompanying picture. It's described as being a simple guardian, often one that asks riddles, and I think it might have some spellcasting or regenerative abilities. Any ideas about what book it's in?