Alien Prey (1977)

 aka Prey

An alien lands on Earth, kills a couple making out in the woods, and assumes the appearance of the male. After wandering onto an estate, he runs into Jessica and Jo.

Jessica owns the estate and Jo lives with her. At first it's difficult to determine if they are sisters, friends, mother/daughter or lovers. But since there's a love scene later, it becomes clear that Jo is her girlfriend, which is unfortunate since she's domineering, jealous, abusive, irrational and doesn't want Jessica to have any contact with anyone else.

The alien, who appears to be injured and introduces himself as Anders Anderson, is invited back to the house by Jessica, much to Jo's annoyance.  Eventually he's invited to dinner and to spend the night.  When out of earshot, Jessica advises Anders to lock his door since she suspects that Jo had a hand in the disappearance of the last man who stayed at the house.

Anders acts odd and Jessica suspects he is from the asylum nearby.  But Jo forbids her to contact the asylum or the police.  Instead she tries to manipulate Anders and Jessica and make them both ill at ease. She makes disparaging remarks about them and when they have a little party, she puts Anders in makeup and a dress. She is desperate to make sure Jessica doesn't connect with Anders.   Surprisingly, although he is an alien, Anders picks up on her control issues immediately.

I am not fond of dull British horror movies of the 1970s. This is mostly talking between the three characters. I don't necessarily mind this if there is tension or suspense, but this just wasn't interesting.  There's a drowning scene which is in slow motion, and never seems to end.  Plus the alien has a dog nose, which makes him look like someone using greasepaint rather than a scary alien.

Dog nose and pointy teeth? Must be an alien.

Vegetarians have an awkward dinner with the alien