2. The story went that Robert Downey, Jr. ad libbed the line, which seemed true enough, until someone found this in a “Buffy the Vampire Slayer” DVD special feature
3. And said:
In his commentary for “The Avengers,” Joss mentions that on the day, RDJ was looking for some new lines that he could play with. Joss threw him the line about shawarma and he ran with it. So yes, there was some improvisation involved, but the idea still came from Joss.