If you grew up with after-school sci-fi matinees on Channel 5’s The Big Show, you quickly learned to watch for the name Ray Harryhausen. It guaranteed sword-fighting skeletons, death-dealing saucers, rampaging dinosaurs, irradiated octopi waging three-tentacled war on San Francisco — each given life and breath by hand through painstaking stop-motion animation. To incorporate these beasts into live-action film, Harryhausen used a process known as “Dynamation,” splitting the background and foreground of the image and placing his creations in between to give the appearance of interaction. Harryhausen’s creations may seem today as antiquated as Méliès’ rocket trip to the moon, but they look and move like the product of a single guiding vision, as if lovingly handmade — which they were. Harryhausen exercised such control over his projects that he’s one of the few technicians in movie history who was more the auteur of his films than the director or screenwriters. The special-effects wizard died May 7 in London, and on what would have been his 93rd birthday, The Belcourt is launching a three-weekend tribute starting with a double feature of two Harryhausen favorites, 1956’s Earth vs. the Flying Saucers and 1957’s 20 Million Miles to Earth (which features perhaps his best-loved creation, the scaly humanoid giant known as the Ymir). Take the kids — or go by yourself and become one again.