And check out Stanley Kubrick's The Shining (1980). The previous hotel caretaker's ghostly, identically dressed daughters hold hands and gaze coldly at little clairvoyant Danny (Danny Lloyd), silent phantoms from a Diane Arbus photograph. The girls provide double the creepiness of Jack Nicholson's manic laugh and axe-wielding antics. Mary Lambert attempts similar spookiness with the appalling Pet Sematary II, except her identically-dressed gruesome twosome become hysterical when confronted with the remains of a litter of savaged kittens. Wimps.
The same insult cannot be levelled at the knife-throwing killer brothers adorning Octopussy (1983): they murder 008 and don't even break into a sweat. While Gremlins II (1990) offers wacky scientist twins (their laboratory is called 'Splice of Life', a play on the name of a US coffee-shop chain) to whom twisted Christopher Lee addresses the apposite remark, 'How's the cloning going?'