The guy at my favorite weapon shop (
Sharp Edge - Home ) is pretty knowledgable on self defense situations. We had a pretty long talk about the pros and cons of pepper spray and tazers.
If you are talking about those hardcore guns that shoot out cables then I gotta say those are pretty damn good, probably better than pepper spray. But, they are VERY expensive. Sure, if you got the cash then it's worth the investment, but too expensive for me and my family for sure.
Many people opt for the cheaper option, which are the Tazers that work on contact only. Apparently pepper spray is faaaaar more effective than those shockers. He said most hardened criminals laugh at those things. He said they cause pain, but the attacker can power through it. I can believe it since I have seen a man getting shot with the cables, and using pure will power, pulling them off and jumping straight up again ready to fight again.
The pepper spray, as we all know, can be resisted. I can prolly link some youtube vids of people doing that. But, for an untrained person, who is likely to struggle with the adrenaline that surges through them, they have more chance of using their pepper spray, than getting it right with high voltage equipment. People have been known to drop their own tazer when they get a fright from the noise/crackle it makes.
Ultimately they all have pros and cons. Most stopping power would be the wire shooting tazer, but it's very pricey. Pepper spray will work most of the time, and is very affordable and compact.
I know people I would probably recommend a tazer rather. My sister asked me if I would buy her a Tazer and I said I would but she should speak to the guy at the store first, and she came back with pepper spray. I would use pepper spray myself. It doesn't rely on a battery which is also a plus.
If you are in the price range of getting one of those expensive Tazers, there is also a gas powered gun ( looks a bit like the gun from robocop but smaller ) which holds up to 8 Pepper Balls which fire at extremely high velocity. That could be a better option for defending your home from intruders.
Master_Huang_zi, ( weird name since you are still in school and don't know how to deal with a bully ). Anyyyyyyyway.
The advice of secretly filming is pretty good. You could try that, and if he suddenly attacks you pepper spray and run. Don't think having a pepper spray/tazer/etc. allows you to just walk up to him and start blasting.
It has to be used with just cause in self defense. If you forget this, you could be the one the authorities want to question.
If he is messing with you in school, just go key the principal's car and then go tell the principal you saw who did and plant the key in his bag. LOL, Just KIDDING !!! If you get expelled from school for doing this, don't come crying to me

.... maybe some itching powder in his sports equipent...... ok never mind me, just go to your guidance teacher and ask advice.
I remember my first day of high school, this guy who didn't know me just walked up to me and said "Hey you! Dog! F***ing Dog! Look at me when I f***ing talk to you Dog! You look like a Dog, etc. etc. etc.".
I just looked at him like he'd made a nasty fart, and walked away. Heard him mumbling in the background. Didn't care. Made some great friends and that dude never messed with me again, even though we were in some of the same classes. Me and my friends were so weird, he probably thought I'd brick him in the head after school or something. LOL.