A lovey dovey couple finds out that the castle next door is home to an evil doctor who has a daughter with a unique cold blooded curse. And you thought your neighbors sucked.
http://www.geocities.com/darksider66/reptile.html
This would make a nice double bill with "Plague of the Zombies," as both films were shot about the same time, in the same location, and making use of much of the same talent, both behind and in front of the camera. "The Reptile" also has the distinction of being one of the few films to deal with the subject werereptilism.