To make this you will need the items in the image above...
Step 2: Preparing The Pen
Start of by dismantling the pen so that there is a clear hole all the way through.
Step 3: Preparing The Party Popper
Simply remove the explosive part by taking off the cardboard disks & confetti then pulling it out with some plyers
Step 4: Assembling
>To assemble start of by putting the explosive through the end of the pen. >Then tape it onto the end of the pen where the button would be as the BB wouldn't fit through this end.
Step 5: End+(Optional)
>Now just put the BB into the end of the pen & full the string to fire. >Optionally you could use the party popper to cover the end to stop some of the pressure escaping. Do this by making the party popper wider at the top by using a knife, then thread the string through & tape up the end.