Benvolio is yet another one of the people Faustus humiliates with the help of Mephistopheles, although, to be honest, we don't feel all that sorry for the guy. He's kind of a jerk.
For one thing, when Faustus attempts to impress the Emperor of Germany by conjuring Alexander the Great, a hung-over Benvolio, who can't even be bothered to come down from his window, mocks Faustus. He doesn't think the conjurer can conjure diddlysquat.
And his chosen form of mockery? Of all things, he cries out that, if Faustus is successful in bringing good ol' Alexander around, he, Benvolio, will turn himself into a stag. A stag! Sure…
Of course, when Faustus is successful he makes sure Benvolio makes good on his bet. As punishment for doubting Faustus's mad skills, he makes horns appear on Benvolio's head, giving the Emperor and his courtiers a good laugh in the process. Sounds like a stag to Shmoop.
Unfortunately, Benvolio is proud, and he can't just let the matter end there. He has to have the last word. And, unlike the peasants Faustus humiliates, Benvolio is actually powerful, with powerful friends (and a whole army) that he enlists to help him kill Faustus. Of course, he fails, and gains another set of horns in the process. When's he gonna learn that Faustus doesn't play?
Benvolio's story-arc provides a lot of comic relief for the play. But it's also a little bit sobering, if you think about it. What Faustus does to Benvolio—making him the butt of everyone's jokes—is really very cruel.
Does Benvolio deserve the punishment Faustus gives him? Probably not. He may be a jerk, but he's hardly a Bad Guy. The purpose of this character is to make us think about this question, and the way Faustus'scharacter is going (nowhere good), in the process.