OK. I would inform your teachers to let them know what's going on. It would be hard to find the victim but it may not be so with the bully. I don't know the social ramifications of that act, but someone of official standing should know something about this.
With that in mind I would say yes, confront him; and if you want to, do so loudly so everyone can hear you. Or, do it with people around to watch. Either one will allow you to have witnesses in case he wants to do violence.
I would let your teacher know so that you also have a person of officiality backing you if anything happens.