Yes there is stretchy filament. I put a YouTube link to a video showing some below. And the video was made in 2013 so think of how much better the quality is now. That would be fun to make! Make all the muscles able to move and bend! And YES- make the eye move!! HA! Then take it further by a removable flexible skin suit! Yea that last one conjured up memories of “Silence of the Lambs” but I can’t help but think how fun it would be to make and how interesting it would be after making it. Sounds like a great project to work on!!