To me it also fell to Tony but just a little later. I loved the way he summed up the situation to Peter as he came on the scene:

"What is this guy's problem, Mr. Stark?"

"He's from space. He came to steal a necklace from a wizard."

It's not that the line was meant to be that funny, but just the way that RDJ collapsed the whole crazy situation and the fact that Peter just goes with it.

Also, just another example of this.