Baker next heard from Cohen two weeks after filming had begun. Cohen had decided to rarely show the infant in the film, and asked Baker to create a "dummy baby" for the actors to react to. Baker constructed the baby with an aluminum wire armature, allowing for articulated limbs and adjustable eyeballs. For close-up shots, Baker created a full-head mutant infant mask, a pair of gloves, and a partial body suit, which were worn by Baker's then-girlfriend and later wife, Elaine Parkyn.
