The dead don’t really feel the need to keep up with the times or, well… anything… actually.  So it’s not too surprising that they have no idea what Chuck is talking about.  And as everyone knows, a joke just isn’t funny if no one gets it.  The dead are not amused.

=Comic transcript=======================
Chuck: I wonder where… What the…? *gasp*

Chuck: I see dead people!
Zombie: ??

Zombie 1: Really?
Zombie 2: You don’t say.
Zombie 3: Not too bright is he?
Chuck: Come on… Haven’t any of you seen the movie?
Zombie 2: Which one?