2 Shy (3x06)
written by Jeffrey Vlaming
MULDER: Okay, it's not yet the finely detailed insanity that you've come to expect from me. It's just a theory, but what if he's not doing this out of a psychotic impulse but rather out of physical hunger? Maybe he needs to replenish this chemical deficiency in order to survive
SCULLY: From a dry skin sample you're concluding what? That he's some kind of fat-sucking vampire?
MULDER: This killer secretes a digestive substance which renders the victims fat…
SCULLY: ….which he ingests before the rest of the body dissolves entirely.
MULDER: There are examples of this in nature, aren't there?
SCULLY: Yes, scorpions predigest their food outside of their body by regurgitating onto their prey but I don't know too many scorpions who surf the internet.