Prank Your Friends? With a Water Bottle?

This is my first instructable, so minimum flaming please.

This is a prank that you can do in about 5 minutes.
It is really easy to do, and can have your friend laughing along with you!

Step 1: Tools and Supplies

What you will need is.....

-X-Acto knife/blade/razor/etc.
-Hot glue, with gun
-2 bottles, doesn't matter, just make sure that one of them is clear
-an extremely thirsty person, doesn't work as well when they aren't that thirsty

Step 2: Cut It Up!

Just take your blade of some sort, and cut very close to the top of the bottle.

Step 3: Rig It Up!

Now, take your clear water bottle
cut up a square slightly bigger than your "cap"

Step 4: Glue It Up!

Now, hot glue your clear part to the "cap" and cut off any excess plastic now, you might not be able to do it later.

Step 5: Fill It Up!

Just fill it mostly with any liquid you desire, or just tap water.

Step 6: Glue It Up! Again!

Now, once the bottle is filled, glue the "cap" back to the bottle. To make it look more legit, try either cutting the excess glue off or using a clear adhesive of some sort, it really doesn't matter, just as long as its on there securely.

Step 7: Now, You Are DONE

Now, just find somebody who is really thirsty, ask them if they want something to drink and done

EFFECT-
when they open the bottle and dump it in their face, nothing or very little liquid comes out!

Step 8: Howa Bout This?

thanks to 11010010110 i got an idea. Instead of cutting the "cap" completely off, fill up the bottle, just above the line where you filled it up, cut a slit in the bottle, take a clear, flattened piece of plastic, size it the best you can, and slip it in there. Glue the slit you cut, and it is now more inconspicuous!

O yea, and just make sure it IS NOT SECURE IN PLACE!!!! so when they pick up the bottle, the plastic will just be forced onto the cap and not allowing any or very little liquid to come out! I haven't tested this, so good luck trying it for whoever wants to!