The set was built on a platform raised four feet above the ground, with trap doors constructed at many points so that ALF could appear almost anywhere; Fusco operated him from underneath, so the unoccupied holes all over the floor were deep and treacherous. The trap doors had to be reset multiple times, sometimes during a single scene. Principal puppeteer Paul Fusco (who was mainly left-handed when puppeteering) used his left hand to control ALF's mouth, while his right hand controlled ALF's right arm. Another puppeteer, Lisa Buckley, who would go on to perform on "Sesame Street", assisted Fusco beneath the stage, operating ALF's left arm. At times when ALF's full body was shown in the sitting position, Lisa controlled ALF's left hand by cable allowing slight finger movements. There was additionally a third puppeteer, Bob Fappiano, who controlled ALF's facial and ear movements via a radio control offscreen. During tapings, Fusco would wear a head-mounted microphone to record ALF's voice. The process resulted in numerous mistakes and retakes, making it impossible to record "ALF" in front of a live audience. A laugh track was added during post-production.