I don't remember that but a lot of his antics seemed to be planned and part of his way of keeping people awake and paying attention. If it is part of his routine I wonder when he added it. I took his courses in 2006-2007.
I took that course in 2015 or 2016, so yeah, I guess that's about a decade in which he could have added it. I just browsed around Chalmers' course pages and am very happy to see that he's still teaching that course.
