Plot: Martin Short breaks down his most iconic roles, including his characters in 'Saturday Night Live,' 'Three Amigos,' 'Mulaney,' 'Second City,' 'Mars Attacks!,' 'Jiminy Glick,' 'The Santa Clause 3: The Escape Clause,' 'Innerspace,' 'Three Fugitives,' 'Father of the Bride,' and 'The Willoughbys. '