Fold a sheet of A4 paper into thirds.
Step Two
Separately, slide a rubber band onto each side of a paperclip.
Step Three
Using sticky tape (the strong kind), tape each rubber band onto the middle third of the paper.
Step Four
Twist the paperclip as much as possible so that the rubber bands are also twisted.
Step Five
Carefully, by keeping the twisted paperclip and rubber bands in place, fold the other thirds of the paper over the paperclip section.
Step Six
Continue to hold the papercliped section in place and put the paper into an envelope for A4 sized papers.
Step Seven
Give envelope to intended victim and tell them to open the envelope. Hear them scream or yelp as the envelope 'mysteriously' buzzes.
Note: if you find that the paperclip unwounds before its in the hands of the victim, place a small square of double sided/double folded tape over the paperclip so that the tape keeps it in place until the whole paper is opened.
Images are hand drawn and provided by me. So if you want to use them, don't forget to credit and link back.