When Troy and Abed are rolling in the giant ball and knock over Starburns, he is standing in a stool. It is there in the shot where he gets knocked over, but in the shot where they roll over him and all subsequent shots in the sequence, the stool is gone.
When questioning LeVar Burton about Star Trek: The Next Generation (1987), Troy mentions that they have never visited a star.
This is incorrect. In the episode Relics (1992) the crew visit a star.