Complex sentence: When Williams was asked to take a seat at the audition, Williams immediately sat on his head on the chair and Marshall cast him on the spot, and later wryly commented that Williams was the only alien who auditioned for the role.
Split into simpler sentences: When Williams was asked to take a seat at the audition, Williams immediately sat on his head on the chair and Marshall cast him on the spot. He later commented that Williams was the only alien who auditioned for the role.