You will need:
a kinder surprise egg
a small rock or ball.
Great use for when your bored. played with my friend 5 hours straight
eat all the chocolate so all thats left is the yellow ball and the stupid toy. open the egg up and take the toy
turn it around an you will see a column. take the lid and rip it along the column and stop at the circle at the bottom.
now it is finished. hold the lid and pull it back so the hinge is touching the circle.put your ammo in and let go. shoots up to 3 meters( if you make it really good.)