It turns out the shawarma line in Marvel’s The Avengers isn’t something that came out of left field. Instead, director Joss Whedon‘s infatuation with the grilled meat stems from his very first television project: Buffy the Vampire Slayer.
The credit goes to YouTube user Buffyfan45 (via /Film), who made the connection between The Avengers and Buffy. There’s a DVD extra on the Buffy the Vampire Slayer: Chosen Collection set that includes the tidbit below about Nicholas Brendon’s audition. According to Whedon, he has “shawarma” to thank for his role.
“Nicky just tore the place apart [during his audition], was just weird. We hadn’t seen it before,” Whedon recalls in the clip. “Afterwards, he was like, ‘Does anybody feel like shawarma? I feel like some shawarma!’ And I was like, ‘This guy speaks to me!’ That was it. I knew there was no other Xander.”
As for the joke in The Avengers, story goes that the original line Iron Man is supposed to say in the script is, “What’s next?” but Robert Downey Jr. wanted something better. Whedon acceded, and somewhere along the way they decided to go with the shawarma line. Regardless of whether it was Downey or Whedon’s suggestion (we’re guessing the latter, based on this clip), the rest, as they say, is history.