For this to be really convincing and spoooky, you could stay in character:
Halloween party attendant: Hi radical_negative_one, what are you dressed as? confederate: radical_negative_one is a p-zombie, who acts just like a real person but is not actually conscious! radical_negative_one: That’s not true, I am conscious! I have qualia and an inner life and everything!
radical_negative_one: (To confederate:) No, you’re the p-zombie, not me! (To Halloween party attendant:) They’re getting everywhere, you know. They look and act just like you and me, physically you can’t tell, but they have no soul! They’re just dead things!! They sound like us, but nothing they say means anything, it’s just noises coming out of a machine!!! Your best friend could be a p-zombie!!!! All your friends could be p-zombies!!!!!
confederate It’s all true! And he’s one of them! Say, how do I know you’re not a zombie?
For this to be really convincing and spoooky, you could stay in character:
Halloween party attendant: Hi radical_negative_one, what are you dressed as?
confederate: radical_negative_one is a p-zombie, who acts just like a real person but is not actually conscious!
radical_negative_one: That’s not true, I am conscious! I have qualia and an inner life and everything!
radical_negative_one: (To confederate:) No, you’re the p-zombie, not me! (To Halloween party attendant:) They’re getting everywhere, you know. They look and act just like you and me, physically you can’t tell, but they have no soul! They’re just dead things!! They sound like us, but nothing they say means anything, it’s just noises coming out of a machine!!! Your best friend could be a p-zombie!!!! All your friends could be p-zombies!!!!!
confederate It’s all true! And he’s one of them! Say, how do I know you’re not a zombie?
confederate: No, radical_negative_one. You are the demons
And then radical_negative_one was a zombie.