So, you wanna be a ninja? Well heres something you might need.

"Caltrops" - A caltrop (calthrop, jack rock, star nail or crow's foot) is a weapon made up of two (or more) sharp nails or spines arranged in such a manner that one of them always points upward from a stable base (for example, a tetrahedron). Caltrops serve to slow down the advance of horses, war elephants, and human troops. It was said to be particularly effective against the soft feet of camels.[1] In more modern times, caltrops are used against wheeled vehicles with pneumatic tires. In Japan such devices were known as makibishi.

Gotta Get them camels!

Step 1: Materials

Materials: Scissors and a peice of sheet metal about 1" X 2".
Actually the size doesn't matter but I like this size.

Or if you are using thicker metal use tin snips

Step 2: Cutting 1

Here is where the scissors are needed.

Cut 2 lines length wize from each end about 1/3 of the way (see picture)

Step 3: Cutting 2

Now

Cut from the... just look at the picture

You want the final out come to look like a squished hour glass

Step 4: Bend

Here might be the hard or easy part. If you have thick sheet metal then find something curved and hammer it into shape.

If you got thin metal from a pop can or what have you then you can just bend it with your fingers.

Postition the metal so the hour

Step 5: HURT PEOPLE!

Now! Throw it on the ground and it will always land with a point up.

If you made it with thin metal it will probly only hurt people with no shoes but if its thick you'll be ripping TROUGH CAMEL FEET!