masking for a single object, not all

What I’m trying to do is animate/etc. a mouth shape that’s shrinkwrapped onto a larger object. I don’t want it to mask the whole thing, just make the larger object disappear only where the mouth shape is. I’d still like the inside surface of the larger object visible so the mouth doesn’t appear as a hole through the entire body. Is there a way to do this?

It appears you are trying to make it to complicated, unless it requires the shrinkwrapper for special reasons. Are you working on something in particular?

I’m trying to make a mouth appear on a squishy softbody head, and am really going for a cartoony look where the smile creeps up around the face. Making a jawbone would be too rigid for the look I’m trying to make. That’s why I wanted to shrinkwrap a mouth shape; so opening, closing and smiling would just be accomplished by resizing the shrinkwrapped object. Of course I want the mouth to appear correct from the side, which is why I posed this question.

What if you did the mouth as a texture, and animated the UV coordinates of that texture?

I found a solution! By inserting a mouth-shaped block partway into the head, then applying an intersect boolean modifier to the head, I was able to get exactly the effect I wanted! Thanks to all those who responded!