Star Trek: Deep Space Nine1993

Joseph Sisko:
Benjamin Lafayette Sisko, what the hell has gotten into your head? You actually thought I was one of them, didn't you?

Captain Sisko:
I don't know. I wasn't sure.

Joseph Sisko:
This business has got you so twisted around, you... you can't think straight. You're seeing shapeshifters everywhere! Maybe you ought to think about something for a minute. If I was a smart shapeshifter, a really good one, the first thing I would do would be to grab some poor soul off the street, absorb every ounce of his blood and let it out on cue whenever someone like you tried to test me. Don't you see? There isn't a test that's been created a smart man can't find his way around.