Eric says on the YouTube post, "TARS robot under construction. Hopefully it will crutch walk. Stay tuned." For those unfamiliar, here is a clip from the movie of TARS in action. It shows TARS and Astronaut Cooper or "Coop," who is played by Matthew McConaughey. Case is another robot in Interstellar. All the robots in the movie are described here, and the links for TARS show the different movements including the "crutch walk."
And here, 'MythBusters' Adam Savage Explains Why Interstellar's TARS Is The Perfect Robot. Adam explains that the plot of the movie left him cold, but that he loved TARS.
Can't wait to see what Eric makes of this!