The mouth is a really good guess! I'll bet that's where it is.
It really kind of bothers me when people call something a hologram when it's not. I don't know much about them, but it's pretty easy to identify things that are definitely not holograms, such as the Pepper's Ghost effect, and projections onto smoke (rats in Indy, Davy Jones).
The apple in Snow White that is not actually there: is this a hologram on not? Just some kind of reflection, right? It looks a little like those tricks you see at kid's museums where there is an illusion of cookies or something reflected in a bowl up into the space/surface above it, and but it's not actually there when you try to touch it. It's very 3-d looking, and in 360 degrees. Are the museum cookies a hologram, or is it called something else?