This probably won't do any damage, it's just meant to annoy people, but anyway...
DISCLAMER: I am not responsible for any injury or damage caused by this to yourself or other people. I am also not responsible for any trouble that you get in with any parents, faculty members, co-workers, bosses, or any other people covered under loco parentis or have authority over you. I am not responsible for anything that is caused by this. HAHAHAHAHAHA! Beware!
And remember, do not fire at face or eyes.
Step 1: Materials
-A 0.7 mm mechanical pencil (preferably with 2 prongs to push out lead.)
-scissors and or pliers
Step 2: Removing the Cap
1. If it is a good quality pencil just screw the tip off to see the lead loader.
2. If it's a very cheap pencil, which actually work better in the end, you use the scissors to wedge the cap on the tip off.
Now you can see the lead loader. If it has 2 prongs, go to the next step, if it has 3, you need to start over with a new pencil.
Step 3: How to Load and Fire the Staples
To fire, pull back the button that you use to lengthen the lead and the ring should push the staple out propelling it toward your helpless unsuspecting target.
Step 4: Optional Stuff
You can also modify the staple using the pliers and scissors. You can cut it in half or do anything as long as it has a folded edge.
The ideal target is the hair or neck because they won't know what hit them and they might find staples in their hair later and say, "Curse you _______!"