The rod-puppet approach was chosen for the production rather than stop-motion animation, which did not provide the required smoothness to appear realistic. As a result, the rod-puppet allowed for a fast alien that could move across surfaces of any orientation and be shot from any angle. This was particularly effective as it was able to accomplish movements not feasible by an actor in a suit. The ⅓-scale puppet was 40 inches long and cast in foam rubber over a bicycle chain armature for flexibility. For moving camera shots, the on-set cameras were equipped with digital recorders to track, pan, tilt, and dolly values. The data output was then taken back to the studio and fed into the motion control cameras with the linear dimensions scaled down to match the puppet.