Moral Conflict

So I first off went to state that I am normally a passive person, not much a person can say to me will really make me mad, or truly upset. And this has happened more so sense I have joined HE and have started meditation and reiki practice. I have really just been able to forgive everyone and let go grudges. Life has been so wonderful until now…

It all began when I started taking a lab class to accompany my bio class. I sat down in an empty table soon to be filled up with in a few minutes by all males. I know none of their names so i’ll describe them as such. One seemed very quiet and shy, the other was a foreign man who spoke pretty good English but still needed some work, and the last one was a kid who seems to be a little slower ( and I have nothing against that just stating my observation). And lastly me, seeing that no one was going to step up I took the role of kinda of the leader of the group and all was good for the first lab. It wasnt until the second lab that I found out that the shy kid was one of the biggest assholes ever!
No sooner than the second lab started I started to realize this kid was a straight dick, but not to me to the was his aggression directed towards it was the slower kid. Now I did not find this funny, but very rude and offensive. So i took the kid aside and told him that he should stop because it wasnt nice.( and the fact that the kid did not comprehend that he was being mad fun of). The asshole basically told me to fuck off and he started to to make smart remarks about everything I did and still mad fun of the other slower kid in the process.
Now this has been going on for a few weeks now and my blood is starting to boil!! Now like I said im usually pretty passive but something about this whole thing is really starting to get to me. The last two classes I really held myself back from punching this kid square in the face. Now I know violence is not the answer, but this kid is built like a twig and he walks around like his the man.
Now personally I want to hit him and just teach him a lesson. But at the same time I know that is not normally not me. I have never really wanted to beat someone up so bad in my life. It pains me too think this way sometimes, because I do not want to be that guy who beats other people up. That will make me on the same level as this kid and I don’t want that.
All I am looking for is a little advice maybe. I have brought this up to many people close to me and no one has told me anything besides just dont beat the kid up. Nothing else, and it’s frustrating cause I am not thinking straight. Thanks to any one who reads all of this and any tips on how to get over this or anything at all will be much appreciated.