Bed Trick: Eddie's shape-shifting abilities allow him to pull this on women.
Freeze-Frame Bonus: When Mulder and Scully go to Eddie's father's house to look for him, watch what happens to the letter 'h' in the Van Blundht name outside the door...
Idiot Ball: Scully notices that "Mulder" is behaving a bit weird, but fails to connect this with the disappearance of their recent shape-shifting suspect (who was using his ability to essentially rape women by impersonating men they were attracted to). Fridge Brilliance suggests that she likes this new Mulder too much to admit her suspicions.
My Nayme Is: Played with. The unusual spelling of Eddie's name is real, but his insistence on the proper spelling and irritation when it's misspelled certainly fit. He probably makes such a big deal out of it because the spelling makes him feel special.
Oh, Crap: When the husband Eddie is impersonating arrives while he's in the bathroom.
Red Herring: The teaser suggests that the case with be connected to alien abductions and medical rapes and impregnations as Amanda said the father of her child is not from this planet. However, it deals with babies having tails.]
Running Gag: Eddie van Blundht's name " The h is silent"