Freeman said he had no idea what was happening when he opened the Ark. He was told to imagine something coming towards him and to scream. The scene's gore did not concern Spielberg and Lucas. Special effects artist Steve Gawley created the Ark's spirits by suspending small robed puppets in a clouded water tank in front of a blue screen. They were shaken to create a natural movement that was composited into the live footage. A Lucasfilm receptionist, dressed in a long white robe, was suspended in the air in front of a blue screen for the close-up of the ghost. She was filmed moving away from the camera and the footage was reversed to create an inhuman movement. Her visage was composited with a skeletal model for the monstrous transformation.