On-set photography would not be allowed while the film was shot to stimulate public and trade interest. Shooting took either five or six weeks, including the special effects sequences. The budget ranged between $700,000 and $800,000. Film critic Kim Newman said the budget was "not expensive", with most of it used for special effects. Some special effects shots were the earliest taken for the picture. For example, shots with Randy Stuart were taken against a black velvet backdrop and then composited with shots of Williams on an enlarged living room set. Their movements were synchronized using negatives from the first exposed scene in the camera gate, with the opposite done for the other scene. Sound production began on May 31. An oversized dollhouse was built for Williams on Stage 28. It had previously been used for The Phantom of the Opera and Dracula. Arnold said he filmed scenes with the cat in a normal studio with an animal trainer who had about 40 identical cats. To coax the cat to approach the dollhouse, Arnold hid food in it so the cat would find a way into the house. Later he timed the cat's reactions and directed Williams accordingly to react to the cat. Arnold first attempted to follow the novel and use a black widow spider. After preliminary tests, he found black widows were too small to use properly in the film. In an interview with Tom Weaver, Randy Stuart said the spiders presented problems. The overhead lamps on the set had to be turned up high, leading to the deaths of 24 tarantulas. They were directed with little puffs of air, a technique which had been used previously in Arnold's film Tarantula. Despite sources suggesting otherwise, the films did not use the same tarantulas. Many of the basement scenes were shot on Stage 12 of Universal Studios which, according to Tom Weaver, was one of the largest sound stages in the world at the time. While trying to find a way to simulate giant drops of water landing, Arnold recalled a time when he was a child and found condoms in his father's drawer. Not knowing what they were, he filled them with water and dropped them. Arnold ordered about 100 condoms and placed them on a treadmill so they would drop in sequence. The flood scene was shot on July 2 and 3. There was a 20-minute delay