The use of the monkey is notable due to Franco's connection with James Dean. Of course Franco actually portrayed Dean on a 2001 made-for-television movie, a fact hilariously referred to in this video of him and his brother rehearsing a scene from the 1955 Dean film Rebel Without a Cause (at around 1:40):
Anyway, I was just wondering who came up with the idea of Franco's character, "Franco," using the toy monkey as the prop. Any fan of James Dean or Rebel Without a Cause will remember the opening sequence in which Dean's character is shown playing with a similar toy monkey among the garbage of a street gutter: