This classic horror movie was one of Roger Corman's first films. 

Not of this Earth

A strange man wearing large dark glasses, Mr Johnson, walks into a doctor's office and demands a blood transfusion.  The nurse says blood tests are needed first, but Mr Johnson refuses.  Mr Johnson speaks with a strange accent and seems unaware of the normal standards of proper behavior.  When he is alone with the doctor, Mr Johnson removes his glasses, revealing that his eyes are large white spheres, like ping pong balls.  He exerts mental control over the doctor, and the doctor gives him the transfusion.  The doctor then instructs the nurse to go as Mr Johnson's private nurse and give him a transfusion every day.

Mr Johnson is revealed to be an alien from a dying planet, sent to see if earth is livable.  His superior tells him there are several phases.  First is to see if Mr Johnson can survive on human blood.  Then he is to send human blood back to them, then send a live human for experimentation.  If all works out, they will take over earth and feed off human blood.

At Mr Johnson's mansion, the nurse moves in.  There is also a driver /  servant named Jeremy.  Jeremy is a slimy ex-convict.  Jeremy tells the nurse of his fears about the situation.  Jeremy has noted that door to door salespersons and homeless bums are brought in, but he has never seen anyone leave.

Mr Johnson finds a lady from his planet in a store.  He is surprised, as he was supposed to be the only one.  She tells him that the situation on the home planet is desperate, and food is in extreme short supply.  The blood samples and human that Mr Johnson sent back were consumed by the leaders, rather than being used for study.  She is near death from malnutrition.  Mr Johnson breaks into the doctor's office and gives her a blood transfusion.  However, this blood was from a dog with rabies that the doctor was using for research.  After Mr Johnson leaves, the the alien lady dies.  When she is found, the doctor calls the police.  She has the same dark glasses as Mr Johnson.  One of the policemen is the boyfriend of the nurse.  He calls to warn her that Mr Johnson is dangerous and to get out.  However, Mr Johnson is listening in on the call.  He tells the nurse that he is going to take her back to his planet with him for study.

The nurse runs away from the house, pursued by Mr Johnson.  She calls her police boyfriend from a park, and he heads over there.  Mr Johnson catches the nurse and does the mind control thing.  He tells her to go to the transporter in the house.  The police man shows up and chases Mr Johnson.  Mr Johnson is trying to escape in his car.  While driving, he tries to do the mind control on the police officer.  It requires direct eye to eye contact, and while looking back at the officer, Mr Johnson drives off a cliff.  The car roles over and explodes, killing Mr Johnson.

The movie ends with the nurse and police man looking at Mr Johnson's grave.  As they leave, we see a man approaching who is wearing the same dark glasses and carrying the same metal case that Mr Johnson always had.  

Thanks Joseph C!