 Prop master Rob Smith created the shapeshifter device and later regretted its design . He had joined the series during its second season , and had to quickly manufacture props while working under time and budget constraints . He explained , " [ My ] first episode we had to make the shape @-@ shifter device , the thing that you put into your mouth and it transforms one person into another person . I was brand new here and I wasn ’ t happy with the way that turned out , and it came back in about 5 or 6 episodes . Every time it came back I was like , ‘ Oh , I wish I could have that time over again to redo this one . " He added , " A lot of the time , I [ didn 't ] actually see [ the prop ] on set , so I watched the episode to see how everything comes together . " 
