The phrase "hollow shell" refers to something that appears whole on the outside, but is empty or lacking substance on the inside.
Sentences with «hollow shell»
The other dolls occupying each level are hollow shells for you to control so that you may progress. (justpushstart.com)
It's a decent enough story and exciting at times, although the characters could certainly be more interesting than the mostly hollow shells that they are here. (consoleob.com)
These little interactions build more stock in these characters, which up until now have just been hollow shells for the class system. (gameluster.com)