How can I get this WIERD guy to leave me alone??? ( 10 points!)?

Well, I'm new to this school and don't really know many people there. So I asked this group of girls if I could sit with them at lunch one day and they said yea. I got along good and we talked almost all lunch but I noticed this strange guy looking at me the whole time we were talking. He was extremely skinny with a jacket zipped up to his neck. He wore gross looking clothes, gles, and make jerking movements the whole time he sat.He introduced himself to me and I was nice back, feeling sorry for the dude. The girls kept whispering that he was flirting with me but I brushed it off. The next day the wierdo asked me out. I crushed his dreams politely and continued being civil to him at lunch, even when he kept pestering me saying, "Can't we at least talk about going out?" A week later he bragged to me saying, " I got a girlfriend! Her name's Rachel! She's hot!". I think the object was to make me jeoulous so I acted all enthusiastic back saying, " Oh way to go buddy!!!" The next day, as I headed to lunch he was running towards me yelling, " Hey! Guess what?? I broke up with my girlfriend! Now we can be together!". I turned him down again, still nicely but begining to get annoyed. Then I started sitting with some other friends at lunch and rarely saw him for like a month. This morning he ran up to me in the hallway before school started asking for my phone number and I very reluctantly gave it to him. At lunch I sat with my other friends and he came running up to my table, having seeked me out. He begged me to come meet his friends so I went, acting pissed off as I followed him. We sat down and he said, " You know, the semester's over and I'm gonna miss you sooo much!" I muttered " Yea, yea" and tried to talk to his friends instead of him. He went on and on. Then I said, with a plan in mind, " You know, I saw Rachel this morning in the hallway. I said hi to her. She seems really nice. You should try to get back with her!" He dropped his yogurt, "What?? But I had my heart set on us being together!" I said, almost sternly, " I don't want to go out with you!" He begged, " Why??? Do you like someone else??" I said, " No, not particulary" and turned away. He kept gonig on and on about his feelings for me and finally the lunch bell rang. I tried to escape so I could tell my friends in Spanish cl what had happened but I heard him again, " I would really like to hug you right now." He held out his arms and I RAN! Then after my 4'th block he was waiting outside my clroom door saying how much he was gonna miss me. ( How did he know my 4'th block???). At first I thought this little crush was cute but now it's starting to get on my nerves. What should I do? I don't want to be too mean but he's REALLY starting to scare me. I've been asked out so many times this year but everyone else just accepts it and moves on when I turn them down. This guy is different. He won't give up. And worst of all, the only man I'll ever love show's absolutely no interest in me so I'm heart broken right now. The last thing I need is this wierd guy in my life. Any advice?