Can anyone give me a good way to get back at someone?

A couple days ago, I got into a verbal conflict with another student in a robotics program I participate in. He said something derogatory about my orientation that offended me, so I started yelling at him about it. After awhile, someone else pulled him out of the room so this didn't become an actual fight. None of that is the real problem. The real problem is that the other day, I was brought into the assistant principal's office. Not just due to the conflict either. Apparently, this person told his mother a, shall we say, "revised" edition of what happened. He told her that after the conflict, after he was out of the room, he heard me say something along the lines of, "I just really wanna stab him so badly." Now, I can't recall having said that, and neither can the 10+ witnesses. Unfortunately, his mother told the assistant principal, and he seems to be going on just this person's words, despite that I listed witnesses. So this supposed "death threat" could get me suspended, if they choose to take his side in order to avoid being sued for being "racist", if you know what I mean. I've thought about pressing charges because he lied in a testimony he signed specifically to get me suspended because he has a problem with who I am, making this a hate crime. The only thing stopping me is not knowing how to get the ball rolling on that. So I'm looking for...alternatives. Something to teach him that it's a bad idea to pick on me, because I will retaliate. But something that he couldn't prove was me...

If it helps, our robotics program participates in a yearly competition in another state, where we stay in hotels for a good couple of days. The possibilities there are pretty open...

Any help with this would be appreciated. I don't plan on doing anything illegal, or physically harmful...maybe just some good pranks to make his life hell. Thank you, I know you guys can help me out here :)